diff --git a/examples/react/start-basic/package.json b/examples/react/start-basic/package.json
index 2fafe201eb..ca5cf158a2 100644
--- a/examples/react/start-basic/package.json
+++ b/examples/react/start-basic/package.json
@@ -14,6 +14,8 @@
     "@tanstack/react-start": "^1.121.0-alpha.19",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
+    "seroval": "^1.3.1",
+    "seroval-plugins": "^1.3.1",
     "tailwind-merge": "^2.6.0",
     "vite": "^6.3.5",
     "zod": "^3.24.2"
diff --git a/examples/react/start-basic/src/router.tsx b/examples/react/start-basic/src/router.tsx
index c76eb0210c..e0b6ee8792 100644
--- a/examples/react/start-basic/src/router.tsx
+++ b/examples/react/start-basic/src/router.tsx
@@ -2,6 +2,16 @@ import { createRouter as createTanStackRouter } from '@tanstack/react-router'
 import { routeTree } from './routeTree.gen'
 import { DefaultCatchBoundary } from './components/DefaultCatchBoundary'
 import { NotFound } from './components/NotFound'
+import { serovalSerializer } from '@tanstack/react-router'
+import { FormDataPlugin, HeadersPlugin } from 'seroval-plugins/web'
+import { createServerFn, createStart } from '@tanstack/react-start'
+
+const fn = createServerFn().handler(() => {
+  return {
+    formData: new FormData(),
+    headers: new Headers(),
+  }
+})
 
 export function createRouter() {
   const router = createTanStackRouter({
@@ -15,6 +25,16 @@ export function createRouter() {
   return router
 }
 
+const start = createStart({
+  serializer: serovalSerializer({ plugins: [FormDataPlugin, HeadersPlugin] }),
+})
+
+declare module '@tanstack/react-start' {
+  interface Register {
+    start: typeof start
+  }
+}
+
 declare module '@tanstack/react-router' {
   interface Register {
     router: ReturnType<typeof createRouter>
diff --git a/packages/react-router/src/fileRoute.ts b/packages/react-router/src/fileRoute.ts
index 0b77e986e7..9b45d06c6a 100644
--- a/packages/react-router/src/fileRoute.ts
+++ b/packages/react-router/src/fileRoute.ts
@@ -17,7 +17,7 @@ import type {
   AnyRouter,
   Constrain,
   ConstrainLiteral,
-  FileBaseRouteOptions,
+  LifecycleRouteOptions,
   FileRoutesByPath,
   LazyRouteOptions,
   RegisteredRouter,
@@ -29,6 +29,7 @@ import type {
   RouteLoaderFn,
   UpdatableRouteOptions,
   UseNavigateResult,
+  StartRegister,
 } from '@tanstack/router-core'
 import type { UseLoaderDepsRoute } from './useLoaderDeps'
 import type { UseLoaderDataRoute } from './useLoaderData'
@@ -76,6 +77,7 @@ export class FileRoute<
   }
 
   createRoute = <
+    TStart = StartRegister,
     TSearchValidator = undefined,
     TParams = ResolveParams<TPath>,
     TRouteContextFn = AnyContext,
@@ -83,8 +85,10 @@ export class FileRoute<
     TLoaderDeps extends Record<string, any> = {},
     TLoaderFn = undefined,
     TChildren = unknown,
+    TLifecycleSerialization = unknown,
   >(
-    options?: FileBaseRouteOptions<
+    options?: LifecycleRouteOptions<
+      TStart,
       TParentRoute,
       TId,
       TPath,
@@ -94,7 +98,8 @@ export class FileRoute<
       TLoaderFn,
       AnyContext,
       TRouteContextFn,
-      TBeforeLoadFn
+      TBeforeLoadFn,
+      TLifecycleSerialization
     > &
       UpdatableRouteOptions<
         TParentRoute,
@@ -109,6 +114,7 @@ export class FileRoute<
         TBeforeLoadFn
       >,
   ): Route<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -122,7 +128,8 @@ export class FileRoute<
     TLoaderDeps,
     TLoaderFn,
     TChildren,
-    unknown
+    unknown,
+    TLifecycleSerialization
   > => {
     warning(
       this.silent,
diff --git a/packages/react-router/src/index.tsx b/packages/react-router/src/index.tsx
index c662c21fc0..95ace662a2 100644
--- a/packages/react-router/src/index.tsx
+++ b/packages/react-router/src/index.tsx
@@ -35,16 +35,17 @@ export {
   createControlledPromise,
   retainSearchParams,
   stripSearchParams,
+  serovalSerializer,
 } from '@tanstack/router-core'
 
 export type {
   AnyRoute,
   StartSerializer,
-  Serializable,
-  SerializerParse,
-  SerializerParseBy,
-  SerializerStringify,
-  SerializerStringifyBy,
+  DefaultTypeSerializable,
+  TypeSerializerParse,
+  TypeSerializerParseBy,
+  TypeSerializerStringify,
+  TypeSerializerStringifyBy,
   DeferredPromiseState,
   DeferredPromise,
   ParsedLocation,
@@ -208,13 +209,11 @@ export type {
   MakeRouteMatchUnion,
   RouteMatch,
   AnyRouteMatch,
-  RouteContextFn,
   RouteContextOptions,
-  BeforeLoadFn,
   BeforeLoadContextOptions,
   ContextOptions,
   RouteOptions,
-  FileBaseRouteOptions,
+  LifecycleRouteOptions,
   BaseRouteOptions,
   UpdatableRouteOptions,
   RouteLoaderFn,
diff --git a/packages/react-router/src/route.tsx b/packages/react-router/src/route.tsx
index d3730e819e..9ea4a7cf2a 100644
--- a/packages/react-router/src/route.tsx
+++ b/packages/react-router/src/route.tsx
@@ -35,6 +35,7 @@ import type {
   RouteOptions,
   RouteTypesById,
   RouterCore,
+  StartRegister,
   ToMaskOptions,
   UseNavigateResult,
 } from '@tanstack/router-core'
@@ -150,6 +151,7 @@ export class RouteApi<
 }
 
 export class Route<
+    in out TStart = StartRegister,
     in out TParentRoute extends RouteConstraints['TParentRoute'] = AnyRoute,
     in out TPath extends RouteConstraints['TPath'] = '/',
     in out TFullPath extends RouteConstraints['TFullPath'] = ResolveFullPath<
@@ -171,8 +173,10 @@ export class Route<
     in out TLoaderFn = undefined,
     in out TChildren = unknown,
     in out TFileRouteTypes = unknown,
+    in out TLifecycleSerialization = unknown,
   >
   extends BaseRoute<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -186,10 +190,12 @@ export class Route<
     TLoaderDeps,
     TLoaderFn,
     TChildren,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
   implements
     RouteCore<
+      TStart,
       TParentRoute,
       TPath,
       TFullPath,
@@ -203,7 +209,8 @@ export class Route<
       TLoaderDeps,
       TLoaderFn,
       TChildren,
-      TFileRouteTypes
+      TFileRouteTypes,
+      TLifecycleSerialization
     >
 {
   /**
@@ -211,6 +218,7 @@ export class Route<
    */
   constructor(
     options?: RouteOptions<
+      TStart,
       TParentRoute,
       TId,
       TCustomId,
@@ -222,7 +230,8 @@ export class Route<
       TLoaderFn,
       TRouterContext,
       TRouteContextFn,
-      TBeforeLoadFn
+      TBeforeLoadFn,
+      TLifecycleSerialization
     >,
   ) {
     super(options)
@@ -283,6 +292,7 @@ export class Route<
 }
 
 export function createRoute<
+  TStart = StartRegister,
   TParentRoute extends RouteConstraints['TParentRoute'] = AnyRoute,
   TPath extends RouteConstraints['TPath'] = '/',
   TFullPath extends RouteConstraints['TFullPath'] = ResolveFullPath<
@@ -302,8 +312,10 @@ export function createRoute<
   TLoaderDeps extends Record<string, any> = {},
   TLoaderFn = undefined,
   TChildren = unknown,
+  TLifecycleSerialization = unknown,
 >(
   options: RouteOptions<
+    TStart,
     TParentRoute,
     TId,
     TCustomId,
@@ -315,9 +327,11 @@ export function createRoute<
     TLoaderFn,
     AnyContext,
     TRouteContextFn,
-    TBeforeLoadFn
+    TBeforeLoadFn,
+    TLifecycleSerialization
   >,
 ): Route<
+  TStart,
   TParentRoute,
   TPath,
   TFullPath,
@@ -330,9 +344,11 @@ export function createRoute<
   TBeforeLoadFn,
   TLoaderDeps,
   TLoaderFn,
-  TChildren
+  TChildren,
+  TLifecycleSerialization
 > {
   return new Route<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -345,36 +361,53 @@ export function createRoute<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TChildren
+    TChildren,
+    TLifecycleSerialization
   >(options)
 }
 
-export type AnyRootRoute = RootRoute<any, any, any, any, any, any, any, any>
+export type AnyRootRoute = RootRoute<
+  any,
+  any,
+  any,
+  any,
+  any,
+  any,
+  any,
+  any,
+  any
+>
 
 export function createRootRouteWithContext<TRouterContext extends {}>() {
   return <
+    TStart = StartRegister,
     TRouteContextFn = AnyContext,
     TBeforeLoadFn = AnyContext,
     TSearchValidator = undefined,
     TLoaderDeps extends Record<string, any> = {},
     TLoaderFn = undefined,
+    TLifecycleSerialization = unknown,
   >(
     options?: RootRouteOptions<
+      TStart,
       TSearchValidator,
       TRouterContext,
       TRouteContextFn,
       TBeforeLoadFn,
       TLoaderDeps,
-      TLoaderFn
+      TLoaderFn,
+      TLifecycleSerialization
     >,
   ) => {
     return createRootRoute<
+      TStart,
       TSearchValidator,
       TRouterContext,
       TRouteContextFn,
       TBeforeLoadFn,
       TLoaderDeps,
-      TLoaderFn
+      TLoaderFn,
+      TLifecycleSerialization
     >(options as any)
   }
 }
@@ -385,6 +418,7 @@ export function createRootRouteWithContext<TRouterContext extends {}>() {
 export const rootRouteWithContext = createRootRouteWithContext
 
 export class RootRoute<
+    in out TStart = StartRegister,
     in out TSearchValidator = undefined,
     in out TRouterContext = {},
     in out TRouteContextFn = AnyContext,
@@ -393,8 +427,10 @@ export class RootRoute<
     in out TLoaderFn = undefined,
     in out TChildren = unknown,
     in out TFileRouteTypes = unknown,
+    in out TLifecycleSerialization = unknown,
   >
   extends BaseRootRoute<
+    TStart,
     TSearchValidator,
     TRouterContext,
     TRouteContextFn,
@@ -402,10 +438,12 @@ export class RootRoute<
     TLoaderDeps,
     TLoaderFn,
     TChildren,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
   implements
     RootRouteCore<
+      TStart,
       TSearchValidator,
       TRouterContext,
       TRouteContextFn,
@@ -413,7 +451,8 @@ export class RootRoute<
       TLoaderDeps,
       TLoaderFn,
       TChildren,
-      TFileRouteTypes
+      TFileRouteTypes,
+      TLifecycleSerialization
     >
 {
   /**
@@ -421,12 +460,14 @@ export class RootRoute<
    */
   constructor(
     options?: RootRouteOptions<
+      TStart,
       TSearchValidator,
       TRouterContext,
       TRouteContextFn,
       TBeforeLoadFn,
       TLoaderDeps,
-      TLoaderFn
+      TLoaderFn,
+      TLifecycleSerialization
     >,
   ) {
     super(options)
@@ -487,22 +528,27 @@ export class RootRoute<
 }
 
 export function createRootRoute<
+  TStart = StartRegister,
   TSearchValidator = undefined,
   TRouterContext = {},
   TRouteContextFn = AnyContext,
   TBeforeLoadFn = AnyContext,
   TLoaderDeps extends Record<string, any> = {},
   TLoaderFn = undefined,
+  TLifecycleSerialization = unknown,
 >(
   options?: RootRouteOptions<
+    TStart,
     TSearchValidator,
     TRouterContext,
     TRouteContextFn,
     TBeforeLoadFn,
     TLoaderDeps,
-    TLoaderFn
+    TLoaderFn,
+    TLifecycleSerialization
   >,
 ): RootRoute<
+  TStart,
   TSearchValidator,
   TRouterContext,
   TRouteContextFn,
@@ -510,15 +556,20 @@ export function createRootRoute<
   TLoaderDeps,
   TLoaderFn,
   unknown,
-  unknown
+  unknown,
+  TLifecycleSerialization
 > {
   return new RootRoute<
+    TStart,
     TSearchValidator,
     TRouterContext,
     TRouteContextFn,
     TBeforeLoadFn,
     TLoaderDeps,
-    TLoaderFn
+    TLoaderFn,
+    unknown,
+    unknown,
+    TLifecycleSerialization
   >(options)
 }
 
@@ -551,6 +602,7 @@ export type ErrorRouteComponent = RouteComponent<ErrorComponentProps>
 export type NotFoundRouteComponent = SyncRouteComponent<NotFoundRouteProps>
 
 export class NotFoundRoute<
+  TStart,
   TParentRoute extends AnyRootRoute,
   TRouterContext = AnyContext,
   TRouteContextFn = AnyContext,
@@ -559,7 +611,9 @@ export class NotFoundRoute<
   TLoaderDeps extends Record<string, any> = {},
   TLoaderFn = undefined,
   TChildren = unknown,
+  TLifecycleSerialization = unknown,
 > extends Route<
+  TStart,
   TParentRoute,
   '/404',
   '/404',
@@ -577,6 +631,7 @@ export class NotFoundRoute<
   constructor(
     options: Omit<
       RouteOptions<
+        TStart,
         TParentRoute,
         string,
         string,
@@ -588,7 +643,8 @@ export class NotFoundRoute<
         TLoaderFn,
         TRouterContext,
         TRouteContextFn,
-        TBeforeLoadFn
+        TBeforeLoadFn,
+        TLifecycleSerialization
       >,
       | 'caseSensitive'
       | 'parseParams'
diff --git a/packages/react-start-client/src/index.tsx b/packages/react-start-client/src/index.tsx
index 3aebc26282..a8e54ab40f 100644
--- a/packages/react-start-client/src/index.tsx
+++ b/packages/react-start-client/src/index.tsx
@@ -9,6 +9,7 @@ export {
   serverOnly,
   clientOnly,
   json,
+  createStart,
 } from '@tanstack/start-client-core'
 export {
   type DehydratedRouter,
@@ -60,6 +61,7 @@ export {
   type FunctionMiddlewareServerFnOptions,
   type FunctionMiddlewareServerNextFn,
   type FunctionServerResultWithContext,
+  type Register,
 } from '@tanstack/start-client-core'
 export { Meta } from './Meta'
 export { Scripts } from './Scripts'
diff --git a/packages/router-core/package.json b/packages/router-core/package.json
index 5a3ea10fd7..c7cae11086 100644
--- a/packages/router-core/package.json
+++ b/packages/router-core/package.json
@@ -61,6 +61,7 @@
   "dependencies": {
     "@tanstack/history": "workspace:*",
     "@tanstack/store": "^0.7.0",
-    "tiny-invariant": "^1.3.3"
+    "tiny-invariant": "^1.3.3",
+    "seroval": "^1.3.1"
   }
 }
diff --git a/packages/router-core/src/fileRoute.ts b/packages/router-core/src/fileRoute.ts
index 2c689c3929..f3e291a0f5 100644
--- a/packages/router-core/src/fileRoute.ts
+++ b/packages/router-core/src/fileRoute.ts
@@ -2,12 +2,13 @@ import type {
   AnyContext,
   AnyPathParams,
   AnyRoute,
-  FileBaseRouteOptions,
+  LifecycleRouteOptions,
   ResolveParams,
   Route,
   RouteConstraints,
   UpdatableRouteOptions,
 } from './route'
+import type { StartRegister } from './start'
 import type { AnyValidator } from './validators'
 
 export interface FileRouteTypes {
@@ -33,6 +34,7 @@ export interface FileRoutesByPath {
 }
 
 export interface FileRouteOptions<
+  TStart,
   TFilePath extends string,
   TParentRoute extends AnyRoute,
   TId extends RouteConstraints['TId'],
@@ -44,7 +46,9 @@ export interface FileRouteOptions<
   TBeforeLoadFn = AnyContext,
   TLoaderDeps extends Record<string, any> = {},
   TLoaderFn = undefined,
-> extends FileBaseRouteOptions<
+  TLifecycleSerialization = unknown,
+> extends LifecycleRouteOptions<
+      TStart,
       TParentRoute,
       TId,
       TPath,
@@ -54,7 +58,9 @@ export interface FileRouteOptions<
       TLoaderFn,
       AnyContext,
       TRouteContextFn,
-      TBeforeLoadFn
+      TBeforeLoadFn,
+      AnyContext,
+      TLifecycleSerialization
     >,
     UpdatableRouteOptions<
       TParentRoute,
@@ -76,6 +82,8 @@ export type CreateFileRoute<
   TPath extends RouteConstraints['TPath'],
   TFullPath extends RouteConstraints['TFullPath'],
 > = <
+  TLifecycleSerialization,
+  TStart = StartRegister,
   TSearchValidator = undefined,
   TParams = ResolveParams<TPath>,
   TRouteContextFn = AnyContext,
@@ -84,6 +92,7 @@ export type CreateFileRoute<
   TLoaderFn = undefined,
 >(
   options?: FileRouteOptions<
+    TStart,
     TFilePath,
     TParentRoute,
     TId,
@@ -94,9 +103,11 @@ export type CreateFileRoute<
     TRouteContextFn,
     TBeforeLoadFn,
     TLoaderDeps,
-    TLoaderFn
+    TLoaderFn,
+    TLifecycleSerialization
   >,
 ) => Route<
+  TStart,
   TParentRoute,
   TPath,
   TFullPath,
@@ -110,7 +121,8 @@ export type CreateFileRoute<
   TLoaderDeps,
   TLoaderFn,
   unknown,
-  unknown
+  unknown,
+  TLifecycleSerialization
 >
 
 export type LazyRouteOptions = Pick<
diff --git a/packages/router-core/src/index.ts b/packages/router-core/src/index.ts
index c0dc5cb2f0..dff77bdc29 100644
--- a/packages/router-core/src/index.ts
+++ b/packages/router-core/src/index.ts
@@ -67,14 +67,19 @@ export type {
 
 export type {
   StartSerializer,
-  Serializable,
-  SerializerParse,
-  SerializerParseBy,
-  SerializerStringify,
-  SerializerStringifyBy,
+  TypeSerializerParse,
+  TypeSerializerParseBy,
+  TypeSerializerStringify,
+  TypeSerializerStringifyBy,
   SerializerExtensions,
+  DefaultTypeSerializable,
+  DefaultTypeSerializer,
+  Serializer,
+  SerovalSerializer,
 } from './serializer'
 
+export { serovalSerializer } from './serializer'
+
 export type { ParsedLocation } from './location'
 export type { Manifest, RouterManagedTag } from './manifest'
 export { isMatch } from './Matches'
@@ -175,13 +180,11 @@ export type {
   ResolveFullPath,
   AnyRouteWithContext,
   RouteOptions,
-  FileBaseRouteOptions,
+  LifecycleRouteOptions,
   BaseRouteOptions,
   UpdatableRouteOptions,
   RouteLoaderFn,
   LoaderFnContext,
-  RouteContextFn,
-  BeforeLoadFn,
   ContextOptions,
   RouteContextOptions,
   BeforeLoadContextOptions,
@@ -418,3 +421,13 @@ export type {
   ValidateUseSearchResult,
   ValidateUseParamsResult,
 } from './typePrimitives'
+
+export type {
+  CreateStartConfig,
+  StartConfig,
+  StartConfigTypes,
+  DefaultStartRegister,
+  StartRegister,
+  AnyStartConfig,
+  InferSerializer,
+} from './start'
diff --git a/packages/router-core/src/route.ts b/packages/router-core/src/route.ts
index 4d55371437..64960d60b7 100644
--- a/packages/router-core/src/route.ts
+++ b/packages/router-core/src/route.ts
@@ -40,6 +40,11 @@ import type {
   ValidatorFn,
   ValidatorObj,
 } from './validators'
+import type {
+  LifecycleSerialization,
+  StartRegister,
+  TypeSerializerStringifyReturnType,
+} from './start'
 
 export type AnyPathParams = {}
 
@@ -390,6 +395,7 @@ export interface RouteTypes<
   in out TLoaderFn,
   in out TChildren,
   in out TFileRouteTypes,
+  in out TLifecycleSerialization,
 > {
   parentRoute: TParentRoute
   path: TPath
@@ -421,6 +427,7 @@ export interface RouteTypes<
   loaderData: ResolveLoaderData<TLoaderFn>
   loaderDeps: TLoaderDeps
   fileRouteTypes: TFileRouteTypes
+  lifecycleSerialization: TLifecycleSerialization
 }
 
 export type ResolveFullPath<
@@ -439,6 +446,7 @@ export type RouteLazyFn<TRoute extends AnyRoute> = (
 ) => TRoute
 
 export type RouteAddChildrenFn<
+  in out TStart,
   in out TParentRoute extends AnyRoute,
   in out TPath extends string,
   in out TFullPath extends string,
@@ -452,12 +460,14 @@ export type RouteAddChildrenFn<
   in out TLoaderDeps extends Record<string, any>,
   in out TLoaderFn,
   in out TFileRouteTypes,
+  in out TLifecycleSerialization,
 > = <const TNewChildren>(
   children: Constrain<
     TNewChildren,
     ReadonlyArray<AnyRoute> | Record<string, AnyRoute>
   >,
 ) => Route<
+  TStart,
   TParentRoute,
   TPath,
   TFullPath,
@@ -471,10 +481,12 @@ export type RouteAddChildrenFn<
   TLoaderDeps,
   TLoaderFn,
   TNewChildren,
-  TFileRouteTypes
+  TFileRouteTypes,
+  TLifecycleSerialization
 >
 
 export type RouteAddFileChildrenFn<
+  in out TStart,
   in out TParentRoute extends AnyRoute,
   in out TPath extends string,
   in out TFullPath extends string,
@@ -488,9 +500,11 @@ export type RouteAddFileChildrenFn<
   in out TLoaderDeps extends Record<string, any>,
   in out TLoaderFn,
   in out TFileRouteTypes,
+  in out TLifecycleSerialization,
 > = <const TNewChildren>(
   children: TNewChildren,
 ) => Route<
+  TStart,
   TParentRoute,
   TPath,
   TFullPath,
@@ -504,10 +518,12 @@ export type RouteAddFileChildrenFn<
   TLoaderDeps,
   TLoaderFn,
   TNewChildren,
-  TFileRouteTypes
+  TFileRouteTypes,
+  TLifecycleSerialization
 >
 
 export type RouteAddFileTypesFn<
+  TStart,
   TParentRoute extends AnyRoute,
   TPath extends string,
   TFullPath extends string,
@@ -521,7 +537,9 @@ export type RouteAddFileTypesFn<
   TLoaderDeps extends Record<string, any>,
   TLoaderFn,
   TChildren,
+  TLifecycleSerialization,
 > = <TNewFileRouteTypes>() => Route<
+  TStart,
   TParentRoute,
   TPath,
   TFullPath,
@@ -535,10 +553,12 @@ export type RouteAddFileTypesFn<
   TLoaderDeps,
   TLoaderFn,
   TChildren,
-  TNewFileRouteTypes
+  TNewFileRouteTypes,
+  TLifecycleSerialization
 >
 
 export interface Route<
+  in out TStart,
   in out TParentRoute extends AnyRoute,
   in out TPath extends string,
   in out TFullPath extends string,
@@ -553,6 +573,7 @@ export interface Route<
   in out TLoaderFn,
   in out TChildren,
   in out TFileRouteTypes,
+  in out TLifecycleSerialization,
 > extends RouteExtensions<TId, TFullPath> {
   path: TPath
   parentRoute: TParentRoute
@@ -571,9 +592,11 @@ export interface Route<
     TLoaderDeps,
     TLoaderFn,
     TChildren,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
   options: RouteOptions<
+    TStart,
     TParentRoute,
     TId,
     TCustomId,
@@ -585,13 +608,15 @@ export interface Route<
     TLoaderFn,
     TRouterContext,
     TRouteContextFn,
-    TBeforeLoadFn
+    TBeforeLoadFn,
+    TLifecycleSerialization
   >
   isRoot: TParentRoute extends AnyRoute ? true : false
   _componentsPromise?: Promise<Array<void>>
   lazyFn?: () => Promise<
     LazyRoute<
       Route<
+        TStart,
         TParentRoute,
         TPath,
         TFullPath,
@@ -605,7 +630,8 @@ export interface Route<
         TLoaderDeps,
         TLoaderFn,
         TChildren,
-        TFileRouteTypes
+        TFileRouteTypes,
+        TLifecycleSerialization
       >
     >
   >
@@ -629,6 +655,7 @@ export interface Route<
   ) => this
   lazy: RouteLazyFn<
     Route<
+      TStart,
       TParentRoute,
       TPath,
       TFullPath,
@@ -642,10 +669,12 @@ export interface Route<
       TLoaderDeps,
       TLoaderFn,
       TChildren,
-      TFileRouteTypes
+      TFileRouteTypes,
+      TLifecycleSerialization
     >
   >
   addChildren: RouteAddChildrenFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -658,9 +687,11 @@ export interface Route<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
   _addFileChildren: RouteAddFileChildrenFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -673,9 +704,11 @@ export interface Route<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
   _addFileTypes: RouteAddFileTypesFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -688,7 +721,8 @@ export interface Route<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TChildren
+    TChildren,
+    TLifecycleSerialization
   >
 }
 
@@ -706,6 +740,8 @@ export type AnyRoute = Route<
   any,
   any,
   any,
+  any,
+  any,
   any
 >
 
@@ -714,6 +750,7 @@ export type AnyRouteWithContext<TContext> = AnyRoute & {
 }
 
 export type RouteOptions<
+  TStart = StartRegister,
   TParentRoute extends AnyRoute = AnyRoute,
   TId extends string = string,
   TCustomId extends string = string,
@@ -726,7 +763,9 @@ export type RouteOptions<
   TRouterContext = {},
   TRouteContextFn = AnyContext,
   TBeforeLoadFn = AnyContext,
+  TLifecycleSerialization = unknown,
 > = BaseRouteOptions<
+  TStart,
   TParentRoute,
   TId,
   TCustomId,
@@ -737,7 +776,8 @@ export type RouteOptions<
   TLoaderFn,
   TRouterContext,
   TRouteContextFn,
-  TBeforeLoadFn
+  TBeforeLoadFn,
+  TLifecycleSerialization
 > &
   UpdatableRouteOptions<
     NoInfer<TParentRoute>,
@@ -752,49 +792,21 @@ export type RouteOptions<
     NoInfer<TBeforeLoadFn>
   >
 
-export type RouteContextFn<
-  in out TParentRoute extends AnyRoute,
-  in out TSearchValidator,
-  in out TParams,
-  in out TRouterContext,
-> = (
-  ctx: RouteContextOptions<
-    TParentRoute,
-    TSearchValidator,
-    TParams,
-    TRouterContext
-  >,
-) => any
-
-export type BeforeLoadFn<
-  in out TParentRoute extends AnyRoute,
-  in out TSearchValidator,
-  in out TParams,
-  in out TRouterContext,
-  in out TRouteContextFn,
-> = (
-  ctx: BeforeLoadContextOptions<
-    TParentRoute,
-    TSearchValidator,
-    TParams,
-    TRouterContext,
-    TRouteContextFn
-  >,
-) => any
-
-export type FileBaseRouteOptions<
-  TParentRoute extends AnyRoute = AnyRoute,
-  TId extends string = string,
-  TPath extends string = string,
-  TSearchValidator = undefined,
-  TParams = {},
-  TLoaderDeps extends Record<string, any> = {},
-  TLoaderFn = undefined,
-  TRouterContext = {},
-  TRouteContextFn = AnyContext,
-  TBeforeLoadFn = AnyContext,
-  TRemountDepsFn = AnyContext,
-> = ParamsOptions<TPath, TParams> & {
+export interface LifecycleRouteOptions<
+  in out TStart = StartRegister,
+  in out TParentRoute extends AnyRoute = AnyRoute,
+  in out TId extends string = string,
+  in out TPath extends string = string,
+  in out TSearchValidator = undefined,
+  in out TParams = {},
+  in out TLoaderDeps extends Record<string, any> = {},
+  in out TLoaderFn = undefined,
+  in out TRouterContext = {},
+  in out TRouteContextFn = AnyContext,
+  in out TBeforeLoadFn = AnyContext,
+  in out TRemountDepsFn = AnyContext,
+  in out TLifecycleSerialization = unknown,
+> extends ParamsOptions<TPath, TParams> {
   validateSearch?: Constrain<TSearchValidator, AnyValidator, DefaultValidator>
 
   shouldReload?:
@@ -820,7 +832,12 @@ export type FileBaseRouteOptions<
         TRouterContext,
         TLoaderDeps
       >,
-    ) => any
+    ) => TypeSerializerStringifyReturnType<
+      TStart,
+      TLoaderFn,
+      TLifecycleSerialization,
+      'context'
+    >
   >
 
   // This async function is called before a route is loaded.
@@ -837,7 +854,12 @@ export type FileBaseRouteOptions<
         TRouterContext,
         TRouteContextFn
       >,
-    ) => any
+    ) => TypeSerializerStringifyReturnType<
+      TStart,
+      TBeforeLoadFn,
+      TLifecycleSerialization,
+      'beforeLoad'
+    >
   >
 
   loaderDeps?: (
@@ -868,11 +890,22 @@ export type FileBaseRouteOptions<
         TRouteContextFn,
         TBeforeLoadFn
       >,
-    ) => any
+    ) => TypeSerializerStringifyReturnType<
+      TStart,
+      TLoaderFn,
+      TLifecycleSerialization,
+      'loader'
+    >
+  >
+
+  lifecycleSerialization?: Constrain<
+    TLifecycleSerialization,
+    LifecycleSerialization
   >
 }
 
 export type BaseRouteOptions<
+  TStart = StartRegister,
   TParentRoute extends AnyRoute = AnyRoute,
   TId extends string = string,
   TCustomId extends string = string,
@@ -884,8 +917,10 @@ export type BaseRouteOptions<
   TRouterContext = {},
   TRouteContextFn = AnyContext,
   TBeforeLoadFn = AnyContext,
+  TLifecycleSerialization = unknown,
 > = RoutePathOptions<TCustomId, TPath> &
-  FileBaseRouteOptions<
+  LifecycleRouteOptions<
+    TStart,
     TParentRoute,
     TId,
     TPath,
@@ -895,7 +930,8 @@ export type BaseRouteOptions<
     TLoaderFn,
     TRouterContext,
     TRouteContextFn,
-    TBeforeLoadFn
+    TBeforeLoadFn,
+    TLifecycleSerialization
   > & {
     getParentRoute: () => TParentRoute
   }
@@ -1206,14 +1242,17 @@ export interface LoaderFnContext<
 }
 
 export type RootRouteOptions<
+  TStart = StartRegister,
   TSearchValidator = undefined,
   TRouterContext = {},
   TRouteContextFn = AnyContext,
   TBeforeLoadFn = AnyContext,
   TLoaderDeps extends Record<string, any> = {},
   TLoaderFn = undefined,
+  TLifecycleSerialization = unknown,
 > = Omit<
   RouteOptions<
+    TStart,
     any, // TParentRoute
     RootRouteId, // TId
     RootRouteId, // TCustomId
@@ -1225,7 +1264,8 @@ export type RootRouteOptions<
     TLoaderFn,
     TRouterContext,
     TRouteContextFn,
-    TBeforeLoadFn
+    TBeforeLoadFn,
+    TLifecycleSerialization
   >,
   | 'path'
   | 'id'
@@ -1290,6 +1330,7 @@ export type NotFoundRouteProps = {
 }
 
 export class BaseRoute<
+  in out TStart = StartRegister,
   in out TParentRoute extends AnyRoute = AnyRoute,
   in out TPath extends string = '/',
   in out TFullPath extends string = ResolveFullPath<TParentRoute, TPath>,
@@ -1304,9 +1345,11 @@ export class BaseRoute<
   in out TLoaderFn = undefined,
   in out TChildren = unknown,
   in out TFileRouteTypes = unknown,
+  in out TLifecycleSerialization = unknown,
 > {
   isRoot: TParentRoute extends AnyRoute ? true : false
   options: RouteOptions<
+    TStart,
     TParentRoute,
     TId,
     TCustomId,
@@ -1318,7 +1361,8 @@ export class BaseRoute<
     TLoaderFn,
     TRouterContext,
     TRouteContextFn,
-    TBeforeLoadFn
+    TBeforeLoadFn,
+    TLifecycleSerialization
   >
 
   // The following properties are set up in this.init()
@@ -1356,6 +1400,7 @@ export class BaseRoute<
   lazyFn?: () => Promise<
     LazyRoute<
       Route<
+        TStart,
         TParentRoute,
         TPath,
         TFullPath,
@@ -1369,7 +1414,8 @@ export class BaseRoute<
         TLoaderDeps,
         TLoaderFn,
         TChildren,
-        TFileRouteTypes
+        TFileRouteTypes,
+        TLifecycleSerialization
       >
     >
   >
@@ -1378,6 +1424,7 @@ export class BaseRoute<
 
   constructor(
     options?: RouteOptions<
+      TStart,
       TParentRoute,
       TId,
       TCustomId,
@@ -1389,7 +1436,8 @@ export class BaseRoute<
       TLoaderFn,
       TRouterContext,
       TRouteContextFn,
-      TBeforeLoadFn
+      TBeforeLoadFn,
+      TLifecycleSerialization
     >,
   ) {
     this.options = (options as any) || {}
@@ -1414,7 +1462,8 @@ export class BaseRoute<
     TLoaderDeps,
     TLoaderFn,
     TChildren,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   >
 
   init = (opts: { originalIndex: number; defaultSsr?: boolean }): void => {
@@ -1422,6 +1471,7 @@ export class BaseRoute<
 
     const options = this.options as
       | (RouteOptions<
+          TStart,
           TParentRoute,
           TId,
           TCustomId,
@@ -1433,7 +1483,8 @@ export class BaseRoute<
           TLoaderFn,
           TRouterContext,
           TRouteContextFn,
-          TBeforeLoadFn
+          TBeforeLoadFn,
+          TLifecycleSerialization
         > &
           RoutePathOptionsIntersection<TCustomId, TPath>)
       | undefined
@@ -1497,6 +1548,7 @@ export class BaseRoute<
   }
 
   addChildren: RouteAddChildrenFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -1509,12 +1561,14 @@ export class BaseRoute<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   > = (children) => {
     return this._addFileChildren(children) as any
   }
 
   _addFileChildren: RouteAddFileChildrenFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -1527,7 +1581,8 @@ export class BaseRoute<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   > = (children) => {
     if (Array.isArray(children)) {
       this.children = children as TChildren
@@ -1541,6 +1596,7 @@ export class BaseRoute<
   }
 
   _addFileTypes: RouteAddFileTypesFn<
+    TStart,
     TParentRoute,
     TPath,
     TFullPath,
@@ -1553,7 +1609,8 @@ export class BaseRoute<
     TBeforeLoadFn,
     TLoaderDeps,
     TLoaderFn,
-    TChildren
+    TChildren,
+    TLifecycleSerialization
   > = () => {
     return this as any
   }
@@ -1574,6 +1631,7 @@ export class BaseRoute<
   }) => {
     Object.assign(this.options, options)
     return this as unknown as BaseRoute<
+      TStart,
       TParentRoute,
       TPath,
       TFullPath,
@@ -1587,7 +1645,8 @@ export class BaseRoute<
       TLoaderDeps,
       TNewLoaderFn,
       TChildren,
-      TFileRouteTypes
+      TFileRouteTypes,
+      TLifecycleSerialization
     >
   }
 
@@ -1611,6 +1670,7 @@ export class BaseRoute<
 
   lazy: RouteLazyFn<
     Route<
+      TStart,
       TParentRoute,
       TPath,
       TFullPath,
@@ -1624,7 +1684,8 @@ export class BaseRoute<
       TLoaderDeps,
       TLoaderFn,
       TChildren,
-      TFileRouteTypes
+      TFileRouteTypes,
+      TLifecycleSerialization
     >
   > = (lazyFn) => {
     this.lazyFn = lazyFn
@@ -1645,6 +1706,7 @@ export class BaseRouteApi<TId, TRouter extends AnyRouter = RegisteredRouter> {
 }
 
 export interface RootRoute<
+  in out TStart = StartRegister,
   in out TSearchValidator = undefined,
   in out TRouterContext = {},
   in out TRouteContextFn = AnyContext,
@@ -1653,7 +1715,9 @@ export interface RootRoute<
   in out TLoaderFn = undefined,
   in out TChildren = unknown,
   in out TFileRouteTypes = unknown,
+  in out TLifecycleSerialization = unknown,
 > extends Route<
+    TStart,
     any, // TParentRoute
     '/', // TPath
     '/', // TFullPath
@@ -1667,10 +1731,12 @@ export interface RootRoute<
     TLoaderDeps,
     TLoaderFn,
     TChildren, // TChildren
-    TFileRouteTypes
+    TFileRouteTypes,
+    TLifecycleSerialization
   > {}
 
 export class BaseRootRoute<
+  in out TStart = StartRegister,
   in out TSearchValidator = undefined,
   in out TRouterContext = {},
   in out TRouteContextFn = AnyContext,
@@ -1679,7 +1745,9 @@ export class BaseRootRoute<
   in out TLoaderFn = undefined,
   in out TChildren = unknown,
   in out TFileRouteTypes = unknown,
+  in out TLifecycleSerialization = unknown,
 > extends BaseRoute<
+  TStart,
   any, // TParentRoute
   '/', // TPath
   '/', // TFullPath
@@ -1693,16 +1761,19 @@ export class BaseRootRoute<
   TLoaderDeps,
   TLoaderFn,
   TChildren, // TChildren
-  TFileRouteTypes
+  TFileRouteTypes,
+  TLifecycleSerialization
 > {
   constructor(
     options?: RootRouteOptions<
+      TStart,
       TSearchValidator,
       TRouterContext,
       TRouteContextFn,
       TBeforeLoadFn,
       TLoaderDeps,
-      TLoaderFn
+      TLoaderFn,
+      TLifecycleSerialization
     >,
   ) {
     super(options as any)
diff --git a/packages/router-core/src/serializer.ts b/packages/router-core/src/serializer.ts
index 58b886bd89..c9844e6df0 100644
--- a/packages/router-core/src/serializer.ts
+++ b/packages/router-core/src/serializer.ts
@@ -1,3 +1,6 @@
+import type { Plugin } from 'seroval'
+import type { Constrain } from './utils'
+
 export interface StartSerializer {
   stringify: (obj: unknown) => string
   parse: (str: string) => unknown
@@ -5,19 +8,29 @@ export interface StartSerializer {
   decode: <T>(value: T) => T
 }
 
-export type SerializerStringifyBy<T, TSerializable> = T extends TSerializable
-  ? T
-  : T extends (...args: Array<any>) => any
-    ? 'Function is not serializable'
-    : { [K in keyof T]: SerializerStringifyBy<T[K], TSerializable> }
+// help me fill in the runtime
+export interface Serializer {
+  '~types': {
+    serializer: unknown
+  }
+  stringify: (obj: unknown) => string
+  parse: (str: string) => unknown
+}
+
+export type TypeSerializerStringifyBy<T, TSerializable> =
+  T extends TSerializable
+    ? T
+    : T extends (...args: Array<any>) => any
+      ? 'Function is not serializable'
+      : { [K in keyof T]: TypeSerializerStringifyBy<T[K], TSerializable> }
 
-export type SerializerParseBy<T, TSerializable> = T extends TSerializable
+export type TypeSerializerParseBy<T, TSerializable> = T extends TSerializable
   ? T
   : unknown extends SerializerExtensions['ReadableStream']
-    ? { [K in keyof T]: SerializerParseBy<T[K], TSerializable> }
+    ? { [K in keyof T]: TypeSerializerParseBy<T[K], TSerializable> }
     : T extends SerializerExtensions['ReadableStream']
       ? ReadableStream
-      : { [K in keyof T]: SerializerParseBy<T[K], TSerializable> }
+      : { [K in keyof T]: TypeSerializerParseBy<T[K], TSerializable> }
 
 export interface DefaultSerializerExtensions {
   ReadableStream: unknown
@@ -25,8 +38,117 @@ export interface DefaultSerializerExtensions {
 
 export interface SerializerExtensions extends DefaultSerializerExtensions {}
 
-export type Serializable = Date | undefined | Error | FormData | bigint
+export type DefaultTypeSerializable =
+  | Date
+  | undefined
+  | Error
+  | FormData
+  | bigint
+
+export type DefaultTypeSerializerStringify<T> = TypeSerializerStringifyBy<
+  T,
+  DefaultTypeSerializable
+>
+
+export type DefaultTypeSerializerParse<T> = TypeSerializerParseBy<
+  T,
+  DefaultTypeSerializable
+>
+
+export interface TypeSerializer {
+  value: unknown
+  parse: unknown
+  stringify: unknown
+}
+
+export interface TypeSerializerValue<T> {
+  value: T
+}
+
+export type TypeSerializerApply<
+  TSerializer extends TypeSerializer,
+  T,
+> = TSerializer & TypeSerializerValue<T>
+
+export interface DefaultTypeSerializer extends TypeSerializer {
+  parse: DefaultTypeSerializerParse<this['value']>
+  stringify: DefaultTypeSerializerStringify<this['value']>
+}
+
+export type TypeSerializerParse<
+  TSerializer extends TypeSerializer,
+  T,
+> = TypeSerializerApply<TSerializer, T>['parse']
+
+export type TypeSerializerStringify<
+  TSerializer extends TypeSerializer,
+  T,
+> = TypeSerializerApply<TSerializer, T>['stringify']
+
+export interface SerovalSerializerOptions<TPlugins> {
+  plugins?: Constrain<TPlugins, ReadonlyArray<Plugin<any, any>>>
+}
+
+export const serovalSerializer = <const TPlugins>(
+  options?: SerovalSerializerOptions<TPlugins>,
+): SerovalSerializer<TPlugins> => {
+  // please help with the runtime
+  return undefined as any
+}
+
+export interface SerovalSerializer<TPlugins> extends Serializer {
+  '~types': {
+    serializer: SerovalTypeSerializer<TPlugins>
+  }
+}
+
+export interface SerovalTypeSerializer<TPlugins> extends TypeSerializer {
+  stringify: SerovalTypeStringify<TPlugins, this['value']>
+  parse: DefaultTypeSerializerParse<this['value']>
+}
+
+export type SerovalTypeStringify<TPlugins, T> = unknown extends T
+  ? T
+  : T extends SerovalTypeSerializable<TPlugins>
+    ? T
+    : T extends (...args: Array<any>) => any
+      ? 'Function is not serializable'
+      : T extends Set<any>
+        ? SerovalTypeSetStringify<TPlugins, T>
+        : T extends Map<any, any>
+          ? SerovalTypeMapStringify<TPlugins, T>
+          : { [K in keyof T]: SerovalTypeStringify<TPlugins, T[K]> }
+
+export type SerovalTypeSerializable<TPlugins> =
+  | RegExp
+  | Date
+  | undefined
+  | string
+  | number
+  | bigint
+  | Error
+  | null
+  | SerovalPluginsTypeSerializable<TPlugins>
+
+export type SerovalTypeSetStringify<TPlugins, T> =
+  T extends Set<infer TItem>
+    ? Set<SerovalTypeStringify<TPlugins, TItem>>
+    : never
 
-export type SerializerStringify<T> = SerializerStringifyBy<T, Serializable>
+export type SerovalTypeMapStringify<TPlugins, T> =
+  T extends Map<infer TKey, infer TValue>
+    ? Map<
+        SerovalTypeStringify<TPlugins, TKey>,
+        SerovalTypeStringify<TPlugins, TValue>
+      >
+    : never
 
-export type SerializerParse<T> = SerializerParseBy<T, Serializable>
+export type SerovalPluginsTypeSerializable<TPlugins> = unknown extends TPlugins
+  ? never
+  : TPlugins extends ReadonlyArray<Plugin<any, any>>
+    ? TPlugins[number] extends infer TPlugin
+      ? TPlugin extends Plugin<infer TValue, any>
+        ? TValue
+        : never
+      : never
+    : never
diff --git a/packages/router-core/src/start.ts b/packages/router-core/src/start.ts
new file mode 100644
index 0000000000..f186dd17aa
--- /dev/null
+++ b/packages/router-core/src/start.ts
@@ -0,0 +1,77 @@
+import type {
+  Serializer,
+  SerovalTypeSerializer,
+  TypeSerializerStringify,
+} from './serializer'
+import type { LooseAsyncReturnType, LooseReturnType } from './utils'
+
+export interface StartConfigTypes<in out TSerializer extends Serializer> {
+  serializer: TSerializer
+}
+
+export interface StartConfig<in out TSerializer extends Serializer> {
+  _types: StartConfigTypes<TSerializer>
+}
+
+export type AnyStartConfig = StartConfig<any>
+
+export interface CreateStartConfig<in out TSerializer extends Serializer> {
+  serializer: TSerializer
+}
+
+export interface DefaultStartRegister {
+  start: AnyStartConfig
+  ssr: boolean
+}
+
+export interface StartRegister extends DefaultStartRegister {}
+
+export type SSREnabled<TStart> = TStart extends DefaultStartRegister
+  ? TStart['ssr']
+  : never
+
+export type InferSerializer<TStart> = TStart extends DefaultStartRegister
+  ? unknown extends TStart['start']['_types']['serializer']
+    ? SerovalTypeSerializer<unknown>
+    : TStart['start']['_types']['serializer']['~types']['serializer']
+  : never
+
+export type TypeSerializerStringifyReturnType<
+  TStart,
+  TFn,
+  TLifecycleSerialization,
+  TLifecycle extends keyof LifecycleSerialization,
+> =
+  false extends SSREnabled<TStart>
+    ? any
+    : false extends IsSerializationEnabled<TLifecycleSerialization, TLifecycle>
+      ? any
+      : TFn extends (...args: Array<any>) => Promise<any>
+        ? Promise<
+            TypeSerializerStringify<
+              InferSerializer<TStart>,
+              LooseAsyncReturnType<TFn>
+            >
+          >
+        : TypeSerializerStringify<InferSerializer<TStart>, LooseReturnType<TFn>>
+
+export interface LifecycleSerialization {
+  context?: boolean
+  beforeLoad?: boolean
+  loader?: boolean
+}
+
+export interface DefaultLifecycleSerialization {
+  context: false
+  beforeLoad: true
+  loader: true
+}
+
+export type IsSerializationEnabled<
+  TLifecycleSerialization,
+  TLifecycle extends keyof LifecycleSerialization,
+> = TLifecycleSerialization extends LifecycleSerialization
+  ? unknown extends TLifecycleSerialization[TLifecycle]
+    ? DefaultLifecycleSerialization[TLifecycle]
+    : TLifecycleSerialization[TLifecycle]
+  : DefaultLifecycleSerialization[TLifecycle]
diff --git a/packages/router-devtools-core/src/BaseTanStackRouterDevtoolsPanel.tsx b/packages/router-devtools-core/src/BaseTanStackRouterDevtoolsPanel.tsx
index a84f318bc6..039177c28d 100644
--- a/packages/router-devtools-core/src/BaseTanStackRouterDevtoolsPanel.tsx
+++ b/packages/router-devtools-core/src/BaseTanStackRouterDevtoolsPanel.tsx
@@ -98,6 +98,7 @@ function RouteComp({
   routerState: Accessor<
     RouterState<
       Route<
+        any,
         any,
         '/',
         '/',
@@ -111,7 +112,8 @@ function RouteComp({
         {},
         undefined,
         any,
-        FileRouteTypes
+        FileRouteTypes,
+        any
       >,
       MakeRouteMatchUnion
     >
diff --git a/packages/solid-router/src/index.tsx b/packages/solid-router/src/index.tsx
index 2d7204db62..a7daa25b35 100644
--- a/packages/solid-router/src/index.tsx
+++ b/packages/solid-router/src/index.tsx
@@ -39,11 +39,11 @@ export {
 
 export type {
   StartSerializer,
-  Serializable,
-  SerializerParse,
-  SerializerParseBy,
-  SerializerStringify,
-  SerializerStringifyBy,
+  DefaultTypeSerializable,
+  TypeSerializerParse,
+  TypeSerializerParseBy,
+  TypeSerializerStringify,
+  TypeSerializerStringifyBy,
   DeferredPromiseState,
   DeferredPromise,
   ParsedLocation,
diff --git a/packages/start-client-core/src/createMiddleware.ts b/packages/start-client-core/src/createMiddleware.ts
index 357adea2f2..1ac65896fe 100644
--- a/packages/start-client-core/src/createMiddleware.ts
+++ b/packages/start-client-core/src/createMiddleware.ts
@@ -7,31 +7,39 @@ import type {
 import type {
   Assign,
   Constrain,
+  DefaultStartRegister,
   Expand,
+  InferSerializer,
   IntersectAssign,
   ResolveValidatorInput,
   ResolveValidatorOutput,
-  SerializerStringify,
+  StartRegister,
+  TypeSerializerStringify,
 } from '@tanstack/router-core'
 
-export function createMiddleware<TType extends MiddlewareType>(
+export function createMiddleware<
+  TType extends MiddlewareType,
+  TStart extends DefaultStartRegister = StartRegister,
+>(
   options: {
     type: TType
     validateClient?: boolean
   },
   __opts?: FunctionMiddlewareOptions<
+    TStart,
     unknown,
     undefined,
     undefined,
     undefined,
     ServerFnResponseType
   >,
-): CreateMiddlewareResult<TType> {
+): CreateMiddlewareResult<TStart, TType> {
   // const resolvedOptions = (__opts || options) as MiddlewareOptions<
   const resolvedOptions = {
     type: 'function',
     ...(__opts ||
       (options as FunctionMiddlewareOptions<
+        TStart,
         unknown,
         undefined,
         undefined,
@@ -66,31 +74,44 @@ export function createMiddleware<TType extends MiddlewareType>(
         Object.assign(resolvedOptions, { server }),
       ) as any
     },
-  } as unknown as CreateMiddlewareResult<TType>
+  } as unknown as CreateMiddlewareResult<TStart, TType>
 }
 
 export type MiddlewareType = 'request' | 'function'
 
-export type CreateMiddlewareResult<TType extends MiddlewareType> =
-  'function' extends TType
-    ? FunctionMiddleware<ServerFnResponseType>
-    : RequestMiddleware
+export type CreateMiddlewareResult<
+  TStart extends DefaultStartRegister,
+  TType extends MiddlewareType,
+> = 'function' extends TType
+  ? FunctionMiddleware<TStart, ServerFnResponseType>
+  : RequestMiddleware
 
 export interface FunctionMiddleware<
+  TStart extends DefaultStartRegister,
   TServerFnResponseType extends ServerFnResponseType,
-> extends FunctionMiddlewareAfterMiddleware<unknown, TServerFnResponseType> {
+> extends FunctionMiddlewareAfterMiddleware<
+    TStart,
+    unknown,
+    TServerFnResponseType
+  > {
   middleware: <const TNewMiddlewares = undefined>(
     middlewares: Constrain<
       TNewMiddlewares,
       ReadonlyArray<AnyFunctionMiddleware>
     >,
-  ) => FunctionMiddlewareAfterMiddleware<TNewMiddlewares, TServerFnResponseType>
+  ) => FunctionMiddlewareAfterMiddleware<
+    TStart,
+    TNewMiddlewares,
+    TServerFnResponseType
+  >
 }
 
 export interface FunctionMiddlewareAfterMiddleware<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TServerFnResponseType extends ServerFnResponseType,
 > extends FunctionMiddlewareWithTypes<
+      TStart,
       TMiddlewares,
       undefined,
       undefined,
@@ -100,16 +121,23 @@ export interface FunctionMiddlewareAfterMiddleware<
       TServerFnResponseType
     >,
     FunctionMiddlewareServer<
+      TStart,
       TMiddlewares,
       undefined,
       undefined,
       undefined,
       TServerFnResponseType
     >,
-    FunctionMiddlewareClient<TMiddlewares, undefined, TServerFnResponseType>,
-    FunctionMiddlewareValidator<TMiddlewares, TServerFnResponseType> {}
+    FunctionMiddlewareClient<
+      TStart,
+      TMiddlewares,
+      undefined,
+      TServerFnResponseType
+    >,
+    FunctionMiddlewareValidator<TStart, TMiddlewares, TServerFnResponseType> {}
 
 export interface FunctionMiddlewareWithTypes<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerContext,
@@ -127,6 +155,7 @@ export interface FunctionMiddlewareWithTypes<
     TClientSendContext
   >
   options: FunctionMiddlewareOptions<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerContext,
@@ -217,6 +246,7 @@ export type AnyFunctionMiddleware = FunctionMiddlewareWithTypes<
   any,
   any,
   any,
+  any,
   any
 >
 
@@ -308,6 +338,7 @@ export type AssignAllClientSendContext<
     >
 
 export interface FunctionMiddlewareOptions<
+  in out TStart extends DefaultStartRegister,
   in out TMiddlewares,
   in out TValidator,
   in out TServerContext,
@@ -318,6 +349,7 @@ export interface FunctionMiddlewareOptions<
   middleware?: TMiddlewares
   validator?: ConstrainValidator<TValidator>
   client?: FunctionMiddlewareClientFn<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerContext,
@@ -325,6 +357,7 @@ export interface FunctionMiddlewareOptions<
     TServerFnResponseType
   >
   server?: FunctionMiddlewareServerFn<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerContext,
@@ -334,18 +367,19 @@ export interface FunctionMiddlewareOptions<
   >
 }
 
-export type FunctionMiddlewareClientNextFn<TMiddlewares> = <
-  TSendContext = undefined,
-  TNewClientContext = undefined,
->(ctx?: {
+export type FunctionMiddlewareClientNextFn<
+  TStart extends DefaultStartRegister,
+  TMiddlewares,
+> = <TSendContext = undefined, TNewClientContext = undefined>(ctx?: {
   context?: TNewClientContext
-  sendContext?: SerializerStringify<TSendContext>
+  sendContext?: TypeSerializerStringify<InferSerializer<TStart>, TSendContext>
   headers?: HeadersInit
 }) => Promise<
   FunctionClientResultWithContext<TMiddlewares, TSendContext, TNewClientContext>
 >
 
 export interface FunctionMiddlewareServer<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerSendContext,
@@ -354,6 +388,7 @@ export interface FunctionMiddlewareServer<
 > {
   server: <TNewServerContext = undefined, TSendContext = undefined>(
     server: FunctionMiddlewareServerFn<
+      TStart,
       TMiddlewares,
       TValidator,
       TServerSendContext,
@@ -362,6 +397,7 @@ export interface FunctionMiddlewareServer<
       TServerFnResponseType
     >,
   ) => FunctionMiddlewareAfterServer<
+    TStart,
     TMiddlewares,
     TValidator,
     TNewServerContext,
@@ -371,7 +407,9 @@ export interface FunctionMiddlewareServer<
     ServerFnResponseType
   >
 }
+
 export type FunctionMiddlewareServerFn<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerSendContext,
@@ -380,6 +418,7 @@ export type FunctionMiddlewareServerFn<
   TServerFnResponseType extends ServerFnResponseType,
 > = (
   options: FunctionMiddlewareServerFnOptions<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerSendContext,
@@ -393,23 +432,25 @@ export type FunctionMiddlewareServerFn<
 >
 
 export interface RequestMiddlewareServerFnOptions<
+  in out TStart extends DefaultStartRegister,
   in out TMiddlewares,
   in out TServerSendContext,
 > {
   request: Request
   context: Expand<AssignAllServerContext<TMiddlewares, TServerSendContext>>
-  next: FunctionMiddlewareServerNextFn<TMiddlewares, TServerSendContext>
+  next: FunctionMiddlewareServerNextFn<TStart, TMiddlewares, TServerSendContext>
   response: Response
   method: Method
   signal: AbortSignal
 }
 
-export type FunctionMiddlewareServerNextFn<TMiddlewares, TServerSendContext> = <
-  TNewServerContext = undefined,
-  TSendContext = undefined,
->(ctx?: {
+export type FunctionMiddlewareServerNextFn<
+  TStart extends DefaultStartRegister,
+  TMiddlewares,
+  TServerSendContext,
+> = <TNewServerContext = undefined, TSendContext = undefined>(ctx?: {
   context?: TNewServerContext
-  sendContext?: SerializerStringify<TSendContext>
+  sendContext?: TypeSerializerStringify<InferSerializer<TStart>, TSendContext>
 }) => Promise<
   FunctionServerResultWithContext<
     TMiddlewares,
@@ -437,6 +478,7 @@ export type FunctionServerResultWithContext<
 }
 
 export interface FunctionMiddlewareServerFnOptions<
+  in out TStart extends DefaultStartRegister,
   in out TMiddlewares,
   in out TValidator,
   in out TServerSendContext,
@@ -444,7 +486,7 @@ export interface FunctionMiddlewareServerFnOptions<
 > {
   data: Expand<IntersectAllValidatorOutputs<TMiddlewares, TValidator>>
   context: Expand<AssignAllServerContext<TMiddlewares, TServerSendContext>>
-  next: FunctionMiddlewareServerNextFn<TMiddlewares, TServerSendContext>
+  next: FunctionMiddlewareServerNextFn<TStart, TMiddlewares, TServerSendContext>
   response: TServerFnResponseType
   method: Method
   filename: string
@@ -474,6 +516,7 @@ export type FunctionMiddlewareServerFnResult<
     >
 
 export interface FunctionMiddlewareAfterServer<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerContext,
@@ -482,6 +525,7 @@ export interface FunctionMiddlewareAfterServer<
   TClientSendContext,
   TServerFnResponseType extends ServerFnResponseType,
 > extends FunctionMiddlewareWithTypes<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerContext,
@@ -492,12 +536,14 @@ export interface FunctionMiddlewareAfterServer<
   > {}
 
 export interface FunctionMiddlewareClient<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerFnResponseType extends ServerFnResponseType,
 > {
   client: <TSendServerContext = undefined, TNewClientContext = undefined>(
     client: FunctionMiddlewareClientFn<
+      TStart,
       TMiddlewares,
       TValidator,
       TSendServerContext,
@@ -505,6 +551,7 @@ export interface FunctionMiddlewareClient<
       TServerFnResponseType
     >,
   ) => FunctionMiddlewareAfterClient<
+    TStart,
     TMiddlewares,
     TValidator,
     TSendServerContext,
@@ -514,6 +561,7 @@ export interface FunctionMiddlewareClient<
 }
 
 export type FunctionMiddlewareClientFn<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TSendContext,
@@ -521,6 +569,7 @@ export type FunctionMiddlewareClientFn<
   TServerFnResponseType extends ServerFnResponseType,
 > = (
   options: FunctionMiddlewareClientFnOptions<
+    TStart,
     TMiddlewares,
     TValidator,
     TServerFnResponseType
@@ -532,6 +581,7 @@ export type FunctionMiddlewareClientFn<
 >
 
 export interface FunctionMiddlewareClientFnOptions<
+  in out TStart extends DefaultStartRegister,
   in out TMiddlewares,
   in out TValidator,
   in out TServerFnResponseType extends ServerFnResponseType,
@@ -542,7 +592,7 @@ export interface FunctionMiddlewareClientFnOptions<
   method: Method
   response: TServerFnResponseType
   signal: AbortSignal
-  next: FunctionMiddlewareClientNextFn<TMiddlewares>
+  next: FunctionMiddlewareClientNextFn<TStart, TMiddlewares>
   filename: string
   functionId: string
   type: ServerFnTypeOrTypeFn<
@@ -579,12 +629,14 @@ export type FunctionClientResultWithContext<
 }
 
 export interface FunctionMiddlewareAfterClient<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerSendContext,
   TClientContext,
   TServerFnResponseType extends ServerFnResponseType,
 > extends FunctionMiddlewareWithTypes<
+      TStart,
       TMiddlewares,
       TValidator,
       undefined,
@@ -594,6 +646,7 @@ export interface FunctionMiddlewareAfterClient<
       TServerFnResponseType
     >,
     FunctionMiddlewareServer<
+      TStart,
       TMiddlewares,
       TValidator,
       TServerSendContext,
@@ -602,12 +655,14 @@ export interface FunctionMiddlewareAfterClient<
     > {}
 
 export interface FunctionMiddlewareValidator<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TServerFnResponseType extends ServerFnResponseType,
 > {
   validator: <TNewValidator>(
     input: ConstrainValidator<TNewValidator>,
   ) => FunctionMiddlewareAfterValidator<
+    TStart,
     TMiddlewares,
     TNewValidator,
     TServerFnResponseType
@@ -615,10 +670,12 @@ export interface FunctionMiddlewareValidator<
 }
 
 export interface FunctionMiddlewareAfterValidator<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TServerFnResponseType extends ServerFnResponseType,
 > extends FunctionMiddlewareWithTypes<
+      TStart,
       TMiddlewares,
       TValidator,
       undefined,
@@ -628,13 +685,19 @@ export interface FunctionMiddlewareAfterValidator<
       ServerFnResponseType
     >,
     FunctionMiddlewareServer<
+      TStart,
       TMiddlewares,
       TValidator,
       undefined,
       undefined,
       TServerFnResponseType
     >,
-    FunctionMiddlewareClient<TMiddlewares, TValidator, ServerFnResponseType> {}
+    FunctionMiddlewareClient<
+      TStart,
+      TMiddlewares,
+      TValidator,
+      ServerFnResponseType
+    > {}
 
 export interface RequestMiddleware
   extends RequestMiddlewareAfterMiddleware<undefined> {
diff --git a/packages/start-client-core/src/createServerFn.ts b/packages/start-client-core/src/createServerFn.ts
index 14c1b26001..3b32ffdde6 100644
--- a/packages/start-client-core/src/createServerFn.ts
+++ b/packages/start-client-core/src/createServerFn.ts
@@ -7,11 +7,14 @@ import { globalMiddleware } from './registerGlobalMiddleware'
 import type {
   AnyValidator,
   Constrain,
+  DefaultStartRegister,
   Expand,
+  InferSerializer,
   ResolveValidatorInput,
-  SerializerParse,
-  SerializerStringify,
-  SerializerStringifyBy,
+  StartRegister,
+  TypeSerializerParse,
+  TypeSerializerStringify,
+  TypeSerializerStringifyBy,
   Validator,
 } from '@tanstack/router-core'
 import type { Readable } from 'node:stream'
@@ -33,6 +36,7 @@ export function createServerFn<
   TResponse = unknown,
   TMiddlewares = undefined,
   TValidator = undefined,
+  TStart extends DefaultStartRegister = StartRegister,
 >(
   options?: {
     method?: TMethod
@@ -40,14 +44,16 @@ export function createServerFn<
     type?: ServerFnType
   },
   __opts?: ServerFnBaseOptions<
+    TStart,
     TMethod,
     TServerFnResponseType,
     TResponse,
     TMiddlewares,
     TValidator
   >,
-): ServerFnBuilder<TMethod, TServerFnResponseType> {
+): ServerFnBuilder<TStart, TMethod, TServerFnResponseType> {
   const resolvedOptions = (__opts || options || {}) as ServerFnBaseOptions<
+    TStart,
     TMethod,
     ServerFnResponseType,
     TResponse,
@@ -67,7 +73,8 @@ export function createServerFn<
         ServerFnResponseType,
         TResponse,
         TMiddlewares,
-        TValidator
+        TValidator,
+        TStart
       >(undefined, Object.assign(resolvedOptions, { middleware })) as any
     },
     validator: (validator) => {
@@ -76,7 +83,8 @@ export function createServerFn<
         ServerFnResponseType,
         TResponse,
         TMiddlewares,
-        TValidator
+        TValidator,
+        TStart
       >(undefined, Object.assign(resolvedOptions, { validator })) as any
     },
     type: (type) => {
@@ -85,7 +93,8 @@ export function createServerFn<
         ServerFnResponseType,
         TResponse,
         TMiddlewares,
-        TValidator
+        TValidator,
+        TStart
       >(undefined, Object.assign(resolvedOptions, { type })) as any
     },
     handler: (...args) => {
@@ -93,8 +102,9 @@ export function createServerFn<
       // in the babel plugin. We need to cast it to the correct
       // function signature post-transformation
       const [extractedFn, serverFn] = args as unknown as [
-        CompiledFetcherFn<TResponse, TServerFnResponseType>,
+        CompiledFetcherFn<TStart, TResponse, TServerFnResponseType>,
         ServerFn<
+          TStart,
           TMethod,
           TServerFnResponseType,
           TMiddlewares,
@@ -113,7 +123,7 @@ export function createServerFn<
 
       const resolvedMiddleware = [
         ...(resolvedOptions.middleware || []),
-        serverFnBaseToMiddleware(resolvedOptions),
+        serverFnBaseToMiddleware(resolvedOptions as never),
       ]
 
       // We want to make sure the new function has the same
@@ -292,6 +302,7 @@ export type CompiledFetcherFnOptions = {
 }
 
 export type Fetcher<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TResponse,
@@ -299,12 +310,14 @@ export type Fetcher<
 > =
   undefined extends IntersectAllValidatorInputs<TMiddlewares, TValidator>
     ? OptionalFetcher<
+        TStart,
         TMiddlewares,
         TValidator,
         TResponse,
         TServerFnResponseType
       >
     : RequiredFetcher<
+        TStart,
         TMiddlewares,
         TValidator,
         TResponse,
@@ -324,16 +337,18 @@ export interface FetcherBase {
 }
 
 export type FetchResult<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TResponse,
   TServerFnResponseType extends ServerFnResponseType,
 > = TServerFnResponseType extends 'raw'
   ? Promise<Response>
   : TServerFnResponseType extends 'full'
-    ? Promise<FullFetcherData<TMiddlewares, TResponse>>
-    : Promise<FetcherData<TResponse>>
+    ? Promise<FullFetcherData<TStart, TMiddlewares, TResponse>>
+    : Promise<FetcherData<TStart, TResponse>>
 
 export interface OptionalFetcher<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TResponse,
@@ -341,10 +356,11 @@ export interface OptionalFetcher<
 > extends FetcherBase {
   (
     options?: OptionalFetcherDataOptions<TMiddlewares, TValidator>,
-  ): FetchResult<TMiddlewares, TResponse, TServerFnResponseType>
+  ): FetchResult<TStart, TMiddlewares, TResponse, TServerFnResponseType>
 }
 
 export interface RequiredFetcher<
+  TStart extends DefaultStartRegister,
   TMiddlewares,
   TValidator,
   TResponse,
@@ -352,7 +368,7 @@ export interface RequiredFetcher<
 > extends FetcherBase {
   (
     opts: RequiredFetcherDataOptions<TMiddlewares, TValidator>,
-  ): FetchResult<TMiddlewares, TResponse, TServerFnResponseType>
+  ): FetchResult<TStart, TMiddlewares, TResponse, TServerFnResponseType>
 }
 
 export type FetcherBaseOptions = {
@@ -373,16 +389,23 @@ export interface RequiredFetcherDataOptions<TMiddlewares, TValidator>
   data: Expand<IntersectAllValidatorInputs<TMiddlewares, TValidator>>
 }
 
-export interface FullFetcherData<TMiddlewares, TResponse> {
+export interface FullFetcherData<
+  TStart extends DefaultStartRegister,
+  TMiddlewares,
+  TResponse,
+> {
   error: unknown
-  result: FetcherData<TResponse>
+  result: FetcherData<TStart, TResponse>
   context: AssignAllClientSendContext<TMiddlewares>
 }
 
-export type FetcherData<TResponse> =
+export type FetcherData<TStart extends DefaultStartRegister, TResponse> =
   TResponse extends JsonResponse<any>
-    ? SerializerParse<ReturnType<TResponse['json']>>
-    : SerializerParse<TResponse>
+    ? TypeSerializerParse<
+        InferSerializer<TStart>,
+        ReturnType<TResponse['json']>
+      >
+    : TypeSerializerParse<InferSerializer<TStart>, TResponse>
 
 export type RscStream<T> = {
   __cacheState: T
@@ -395,13 +418,17 @@ export type ServerFnResponseType = 'data' | 'full' | 'raw'
 export type RawResponse = Response | ReadableStream | Readable | null | string
 
 export type ServerFnReturnType<
+  TStart extends DefaultStartRegister,
   TServerFnResponseType extends ServerFnResponseType,
   TResponse,
 > = TServerFnResponseType extends 'raw'
   ? RawResponse | Promise<RawResponse>
-  : Promise<SerializerStringify<TResponse>> | SerializerStringify<TResponse>
+  :
+      | Promise<TypeSerializerStringify<InferSerializer<TStart>, TResponse>>
+      | TypeSerializerStringify<InferSerializer<TStart>, TResponse>
 
 export type ServerFn<
+  TStart extends DefaultStartRegister,
   TMethod,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
@@ -409,13 +436,13 @@ export type ServerFn<
   TResponse,
 > = (
   ctx: ServerFnCtx<TMethod, TServerFnResponseType, TMiddlewares, TValidator>,
-) => ServerFnReturnType<TServerFnResponseType, TResponse>
+) => ServerFnReturnType<TStart, TServerFnResponseType, TResponse>
 
 export interface ServerFnCtx<
-  TMethod,
-  TServerFnResponseType extends ServerFnResponseType,
-  TMiddlewares,
-  TValidator,
+  in out TMethod,
+  in out TServerFnResponseType extends ServerFnResponseType,
+  in out TMiddlewares,
+  in out TValidator,
 > {
   method: TMethod
   response: TServerFnResponseType
@@ -425,17 +452,19 @@ export interface ServerFnCtx<
 }
 
 export type CompiledFetcherFn<
+  TStart extends DefaultStartRegister,
   TResponse,
   TServerFnResponseType extends ServerFnResponseType,
 > = {
   (
     opts: CompiledFetcherFnOptions &
-      ServerFnBaseOptions<Method, TServerFnResponseType>,
+      ServerFnBaseOptions<TStart, Method, TServerFnResponseType>,
   ): Promise<TResponse>
   url: string
 }
 
 export type ServerFnBaseOptions<
+  TStart extends DefaultStartRegister,
   TMethod extends Method = 'GET',
   TServerFnResponseType extends ServerFnResponseType = 'data',
   TResponse = unknown,
@@ -447,8 +476,9 @@ export type ServerFnBaseOptions<
   validateClient?: boolean
   middleware?: Constrain<TMiddlewares, ReadonlyArray<AnyFunctionMiddleware>>
   validator?: ConstrainValidator<TInput>
-  extractedFn?: CompiledFetcherFn<TResponse, TServerFnResponseType>
+  extractedFn?: CompiledFetcherFn<TStart, TResponse, TServerFnResponseType>
   serverFn?: ServerFn<
+    TStart,
     TMethod,
     TServerFnResponseType,
     TMiddlewares,
@@ -464,7 +494,7 @@ export type ServerFnBaseOptions<
   >
 }
 
-export type ValidatorInputStringify<TValidator> = SerializerStringifyBy<
+export type ValidatorInputStringify<TValidator> = TypeSerializerStringifyBy<
   ResolveValidatorInput<TValidator>,
   Date | undefined | FormData
 >
@@ -483,6 +513,7 @@ export type ConstrainValidator<TValidator> =
   | ValidatorSerializerStringify<TValidator>
 
 export interface ServerFnMiddleware<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TValidator,
@@ -493,6 +524,7 @@ export interface ServerFnMiddleware<
       ReadonlyArray<AnyFunctionMiddleware>
     >,
   ) => ServerFnAfterMiddleware<
+    TStart,
     TMethod,
     TServerFnResponseType,
     TNewMiddlewares,
@@ -501,21 +533,41 @@ export interface ServerFnMiddleware<
 }
 
 export interface ServerFnAfterMiddleware<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
   TValidator,
-> extends ServerFnValidator<TMethod, TServerFnResponseType, TMiddlewares>,
-    ServerFnTyper<TMethod, TServerFnResponseType, TMiddlewares, TValidator>,
-    ServerFnHandler<TMethod, TServerFnResponseType, TMiddlewares, TValidator> {}
+> extends ServerFnValidator<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TMiddlewares
+    >,
+    ServerFnTyper<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TMiddlewares,
+      TValidator
+    >,
+    ServerFnHandler<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TMiddlewares,
+      TValidator
+    > {}
 
 export type ValidatorFn<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
 > = <TValidator>(
   validator: ConstrainValidator<TValidator>,
 ) => ServerFnAfterValidator<
+  TStart,
   TMethod,
   TServerFnResponseType,
   TMiddlewares,
@@ -523,24 +575,44 @@ export type ValidatorFn<
 >
 
 export interface ServerFnValidator<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
 > {
-  validator: ValidatorFn<TMethod, TServerFnResponseType, TMiddlewares>
+  validator: ValidatorFn<TStart, TMethod, TServerFnResponseType, TMiddlewares>
 }
 
 export interface ServerFnAfterValidator<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
   TValidator,
-> extends ServerFnMiddleware<TMethod, TServerFnResponseType, TValidator>,
-    ServerFnTyper<TMethod, TServerFnResponseType, TMiddlewares, TValidator>,
-    ServerFnHandler<TMethod, TServerFnResponseType, TMiddlewares, TValidator> {}
+> extends ServerFnMiddleware<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TValidator
+    >,
+    ServerFnTyper<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TMiddlewares,
+      TValidator
+    >,
+    ServerFnHandler<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      TMiddlewares,
+      TValidator
+    > {}
 
 // Typer
 export interface ServerFnTyper<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
@@ -554,6 +626,7 @@ export interface ServerFnTyper<
       TValidator
     >,
   ) => ServerFnAfterTyper<
+    TStart,
     TMethod,
     TServerFnResponseType,
     TMiddlewares,
@@ -578,11 +651,13 @@ export type ServerFnTypeOrTypeFn<
     ) => ServerFnType)
 
 export interface ServerFnAfterTyper<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
   TValidator,
 > extends ServerFnHandler<
+    TStart,
     TMethod,
     TServerFnResponseType,
     TMiddlewares,
@@ -591,6 +666,7 @@ export interface ServerFnAfterTyper<
 
 // Handler
 export interface ServerFnHandler<
+  TStart extends DefaultStartRegister,
   TMethod extends Method,
   TServerFnResponseType extends ServerFnResponseType,
   TMiddlewares,
@@ -598,23 +674,38 @@ export interface ServerFnHandler<
 > {
   handler: <TNewResponse>(
     fn?: ServerFn<
+      TStart,
       TMethod,
       TServerFnResponseType,
       TMiddlewares,
       TValidator,
       TNewResponse
     >,
-  ) => Fetcher<TMiddlewares, TValidator, TNewResponse, TServerFnResponseType>
+  ) => Fetcher<
+    TStart,
+    TMiddlewares,
+    TValidator,
+    TNewResponse,
+    TServerFnResponseType
+  >
 }
 
 export interface ServerFnBuilder<
+  TStart extends DefaultStartRegister,
   TMethod extends Method = 'GET',
   TServerFnResponseType extends ServerFnResponseType = 'data',
-> extends ServerFnMiddleware<TMethod, TServerFnResponseType, undefined>,
-    ServerFnValidator<TMethod, TServerFnResponseType, undefined>,
-    ServerFnTyper<TMethod, TServerFnResponseType, undefined, undefined>,
-    ServerFnHandler<TMethod, TServerFnResponseType, undefined, undefined> {
+> extends ServerFnMiddleware<TStart, TMethod, TServerFnResponseType, undefined>,
+    ServerFnValidator<TStart, TMethod, TServerFnResponseType, undefined>,
+    ServerFnTyper<TStart, TMethod, TServerFnResponseType, undefined, undefined>,
+    ServerFnHandler<
+      TStart,
+      TMethod,
+      TServerFnResponseType,
+      undefined,
+      undefined
+    > {
   options: ServerFnBaseOptions<
+    TStart,
     TMethod,
     TServerFnResponseType,
     unknown,
diff --git a/packages/start-client-core/src/createStart.ts b/packages/start-client-core/src/createStart.ts
new file mode 100644
index 0000000000..19844de8a8
--- /dev/null
+++ b/packages/start-client-core/src/createStart.ts
@@ -0,0 +1,17 @@
+import type {
+  CreateStartConfig as CreateStartConfigCore,
+  Serializer,
+  StartConfig as StartConfigCore,
+} from '@tanstack/router-core'
+
+export interface CreateStartConfig<in out TSerializer extends Serializer>
+  extends CreateStartConfigCore<TSerializer> {}
+
+export interface StartConfig<in out TSerializer extends Serializer>
+  extends StartConfigCore<TSerializer> {}
+
+export const createStart = <TSerializer extends Serializer>(
+  config: CreateStartConfig<TSerializer>,
+): StartConfig<TSerializer> => {
+  return undefined as unknown as StartConfig<TSerializer>
+}
diff --git a/packages/start-client-core/src/index.tsx b/packages/start-client-core/src/index.tsx
index 5c409dab00..84fec1f42a 100644
--- a/packages/start-client-core/src/index.tsx
+++ b/packages/start-client-core/src/index.tsx
@@ -86,3 +86,9 @@ export {
   serverFnStaticCache,
   executeMiddleware,
 } from './createServerFn'
+
+export type { StartRegister as Register } from '@tanstack/router-core'
+
+export type { CreateStartConfig, StartConfig } from './createStart'
+
+export { createStart } from './createStart'
diff --git a/packages/start-client-core/src/tests/createServerMiddleware.test-d.ts b/packages/start-client-core/src/tests/createServerMiddleware.test-d.ts
index 5e61c970c8..0b6b3f2cdf 100644
--- a/packages/start-client-core/src/tests/createServerMiddleware.test-d.ts
+++ b/packages/start-client-core/src/tests/createServerMiddleware.test-d.ts
@@ -442,7 +442,7 @@ test('createMiddleware merges server context and client context, sends server co
           fromClient3: string
           fromClient4: string
         }
-        sendContext: { toServer1: 'toServer1' }
+        sendContext: { toServer1: string }
         headers: HeadersInit
       }>()
 
@@ -453,7 +453,7 @@ test('createMiddleware merges server context and client context, sends server co
         fromServer1: string
         fromServer2: string
         fromServer3: string
-        toServer1: 'toServer1'
+        toServer1: string
       }>()
 
       const result = await options.next({
@@ -468,7 +468,7 @@ test('createMiddleware merges server context and client context, sends server co
             fromServer4: string
           }
           sendContext: {
-            toClient1: 'toClient1'
+            toClient1: string
           }
         }
         context: {
@@ -476,9 +476,9 @@ test('createMiddleware merges server context and client context, sends server co
           fromServer2: string
           fromServer3: string
           fromServer4: string
-          toServer1: 'toServer1'
+          toServer1: string
         }
-        sendContext: { toClient1: 'toClient1' }
+        sendContext: { toClient1: string }
       }>()
 
       return result
@@ -507,9 +507,9 @@ test('createMiddleware merges server context and client context, sends server co
           fromClient3: string
           fromClient4: string
           fromClient5: string
-          toClient1: 'toClient1'
+          toClient1: string
         }
-        sendContext: { toServer1: 'toServer1'; toServer2: 'toServer2' }
+        sendContext: { toServer1: string; toServer2: string }
         headers: HeadersInit
       }>()
 
@@ -521,8 +521,8 @@ test('createMiddleware merges server context and client context, sends server co
         fromServer2: string
         fromServer3: string
         fromServer4: string
-        toServer1: 'toServer1'
-        toServer2: 'toServer2'
+        toServer1: string
+        toServer2: string
       }>()
 
       const result = await options.next({
@@ -537,7 +537,7 @@ test('createMiddleware merges server context and client context, sends server co
             fromServer5: string
           }
           sendContext: {
-            toClient2: 'toClient2'
+            toClient2: string
           }
         }
         context: {
@@ -546,10 +546,10 @@ test('createMiddleware merges server context and client context, sends server co
           fromServer3: string
           fromServer4: string
           fromServer5: string
-          toServer1: 'toServer1'
-          toServer2: 'toServer2'
+          toServer1: string
+          toServer2: string
         }
-        sendContext: { toClient1: 'toClient1'; toClient2: 'toClient2' }
+        sendContext: { toClient1: string; toClient2: string }
       }>()
 
       return result
diff --git a/packages/start-server-core/src/index.tsx b/packages/start-server-core/src/index.tsx
index 9337b7c4cd..6e8cc456ba 100644
--- a/packages/start-server-core/src/index.tsx
+++ b/packages/start-server-core/src/index.tsx
@@ -20,3 +20,9 @@ export * from './h3'
 
 export { createServerRoute, createServerFileRoute } from './serverRoute'
 export type { CreateServerFileRoute } from './serverRoute'
+
+declare module '@tanstack/router-core' {
+  export interface StartRegister {
+    ssr: true
+  }
+}
diff --git a/packages/start-server-functions-fetcher/src/index.ts b/packages/start-server-functions-fetcher/src/index.ts
index 8908d0652c..03b72bb56e 100644
--- a/packages/start-server-functions-fetcher/src/index.ts
+++ b/packages/start-server-functions-fetcher/src/index.ts
@@ -18,7 +18,12 @@ export async function serverFnFetcher(
   // If createServerFn was used to wrap the fetcher,
   // We need to handle the arguments differently
   if (isPlainObject(_first) && _first.method) {
-    const first = _first as FunctionMiddlewareClientFnOptions<any, any, any> & {
+    const first = _first as FunctionMiddlewareClientFnOptions<
+      any,
+      any,
+      any,
+      any
+    > & {
       headers: HeadersInit
     }
     const type = first.data instanceof FormData ? 'formData' : 'payload'
@@ -92,7 +97,7 @@ export async function serverFnFetcher(
 }
 
 function getFetcherRequestOptions(
-  opts: FunctionMiddlewareClientFnOptions<any, any, any>,
+  opts: FunctionMiddlewareClientFnOptions<any, any, any, any>,
 ) {
   if (opts.method === 'POST') {
     if (opts.data instanceof FormData) {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 26c3cc387a..a16aafd83e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -4297,6 +4297,12 @@ importers:
       react-dom:
         specifier: ^19.0.0
         version: 19.0.0(react@19.0.0)
+      seroval:
+        specifier: ^1.3.1
+        version: 1.3.1
+      seroval-plugins:
+        specifier: ^1.3.1
+        version: 1.3.1(seroval@1.3.1)
       tailwind-merge:
         specifier: ^2.6.0
         version: 2.6.0
@@ -6053,6 +6059,9 @@ importers:
       '@tanstack/store':
         specifier: ^0.7.0
         version: 0.7.0
+      seroval:
+        specifier: ^1.3.1
+        version: 1.3.1
       tiny-invariant:
         specifier: ^1.3.3
         version: 1.3.3
@@ -13974,14 +13983,14 @@ packages:
   serialize-javascript@6.0.2:
     resolution: {integrity: sha512-Saa1xPByTTq2gdeFZYLLo+RFE35NHZkAbqZeWNd3BpzppeVisAqpDjcp8dyf6uIvEqJRd46jemmyA4iFIeVk8g==}
 
-  seroval-plugins@1.2.0:
-    resolution: {integrity: sha512-hULTbfzSe81jGWLH8TAJjkEvw6JWMqOo9Uq+4V4vg+HNq53hyHldM9ZOfjdzokcFysiTp9aFdV2vJpZFqKeDjQ==}
+  seroval-plugins@1.3.1:
+    resolution: {integrity: sha512-dOlUoiI3fgZbQIcj6By+l865pzeWdP3XCSLdI3xlKnjCk5983yLWPsXytFOUI0BUZKG9qwqbj78n9yVcVwUqaQ==}
     engines: {node: '>=10'}
     peerDependencies:
       seroval: ^1.0
 
-  seroval@1.2.0:
-    resolution: {integrity: sha512-GURoU99ko2UiAgUC3qDCk59Jb3Ss4Po8VIMGkG8j5PFo2Q7y0YSMP8QG9NuL/fJCoTz9V1XZUbpNIMXPOfaGpA==}
+  seroval@1.3.1:
+    resolution: {integrity: sha512-F+T9EQPdLzgdewgxnBh4mSc+vde+EOkU6dC9BDuu/bfGb+UyUlqM6t8znFCTPQSuai/ZcfFg0gu79h+bVW2O0w==}
     engines: {node: '>=10'}
 
   serve-index@1.9.1:
@@ -23207,11 +23216,11 @@ snapshots:
     dependencies:
       randombytes: 2.1.0
 
-  seroval-plugins@1.2.0(seroval@1.2.0):
+  seroval-plugins@1.3.1(seroval@1.3.1):
     dependencies:
-      seroval: 1.2.0
+      seroval: 1.3.1
 
-  seroval@1.2.0: {}
+  seroval@1.3.1: {}
 
   serve-index@1.9.1:
     dependencies:
@@ -23345,8 +23354,8 @@ snapshots:
   solid-js@1.9.5:
     dependencies:
       csstype: 3.1.3
-      seroval: 1.2.0
-      seroval-plugins: 1.2.0(seroval@1.2.0)
+      seroval: 1.3.1
+      seroval-plugins: 1.3.1(seroval@1.3.1)
 
   solid-refresh@0.6.3(solid-js@1.9.5):
     dependencies: