From 52d39ab157f37d2abc1179e7e779f4eeecdbade5 Mon Sep 17 00:00:00 2001
From: Mathieu Post <mathieupost@gmail.com>
Date: Thu, 13 Nov 2025 14:59:41 +0100
Subject: [PATCH 1/2] docs(react-start): serialization adapters

---
 .../framework/react/guide/server-functions.md | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/docs/start/framework/react/guide/server-functions.md b/docs/start/framework/react/guide/server-functions.md
index 2cbbdf0dde6..b2eb913ab02 100644
--- a/docs/start/framework/react/guide/server-functions.md
+++ b/docs/start/framework/react/guide/server-functions.md
@@ -270,6 +270,31 @@ export default defineConfig({
 })
 ```
 
+### Custom serialization adapters
+
+You can create custom serialization adapters to handle complex types that can't be serialized by default.
+
+Example:
+
+```ts
+// src/start.ts
+import { createStart } from "@tanstack/react-start";
+import { createSerializationAdapter } from "@tanstack/react-router";
+
+const bigIntAdapter = createSerializationAdapter({
+  key: "bigint",
+  test: (value: unknown): value is bigint => typeof value === "bigint",
+  toSerializable: (bigInt) => bigInt.toString(),
+  fromSerializable: (value) => BigInt(value),
+});
+
+export const startInstance = createStart(() => {
+  return {
+    serializationAdapters: [bigIntAdapter],
+  };
+});
+```
+
 ---
 
 > **Note**: Server functions use a compilation process that extracts server code from client bundles while maintaining seamless calling patterns. On the client, calls become `fetch` requests to the server.

From 02f14390b322e89fc7ac476e3d5c3182ce913547 Mon Sep 17 00:00:00 2001
From: Mathieu Post <mathieupost@gmail.com>
Date: Tue, 25 Nov 2025 12:08:21 +0100
Subject: [PATCH 2/2] docs(solid-start): serialization adapters

---
 .../framework/solid/guide/server-functions.md | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/docs/start/framework/solid/guide/server-functions.md b/docs/start/framework/solid/guide/server-functions.md
index 35d8fb58a98..a654b904c0e 100644
--- a/docs/start/framework/solid/guide/server-functions.md
+++ b/docs/start/framework/solid/guide/server-functions.md
@@ -7,3 +7,28 @@ replace:
     '@tanstack/react-router': '@tanstack/solid-router',
   }
 ---
+
+### Custom serialization adapters
+
+You can create custom serialization adapters to handle complex types that can't be serialized by default.
+
+Example:
+
+```ts
+// src/start.ts
+import { createStart } from '@tanstack/solid-start'
+import { createSerializationAdapter } from '@tanstack/solid-router'
+
+const bigIntAdapter = createSerializationAdapter({
+  key: 'bigint',
+  test: (value: unknown): value is bigint => typeof value === 'bigint',
+  toSerializable: (bigInt) => bigInt.toString(),
+  fromSerializable: (value) => BigInt(value),
+})
+
+export const startInstance = createStart(() => {
+  return {
+    serializationAdapters: [bigIntAdapter],
+  }
+})
+```