LangGraph v1 migration guide

Migrate a codebase to LangGraph v1.

Migrate this codebase to LangGraph v1 (requires @langchain/langgraph and @langchain/core at v1, plus langchain at v1 when migrating from createReactAgent, and Node.js 22+).

Key changes:

Upgrade packages: install @langchain/langgraph@latest and @langchain/core@latest. If you use createReactAgent, also install langchain@latest.
createReactAgent → createAgent: replace import { createReactAgent } from "@langchain/langgraph/prebuilts" with import { createAgent } from "langchain". Rename prompt to systemPrompt.
Typed interrupts: define interrupt types at graph construction via an interrupts config on StateGraph.
toLangGraphEventStream removed: use graph.stream with an encoding option (for example "text/event-stream") instead of toLangGraphEventStream / toLangGraphEventStreamResponse.
useStream: supports custom transports.
Build outputs: do not import from package dist/ paths; use the public module exports.

Search the codebase for createReactAgent, toLangGraphEventStream, toLangGraphEventStreamResponse, and @langchain/langgraph/prebuilts, and apply the necessary changes. Flag anything that cannot be migrated automatically.

This guide outlines changes in LangGraph v1 and how to migrate from previous versions. For a high-level overview of what's new, see the release notes.

To upgrade,

npm

pnpm

yarn

bun

npm install @langchain/langgraph@latest @langchain/core@latest

pnpm add @langchain/langgraph@latest @langchain/core@latest

yarn add @langchain/langgraph@latest @langchain/core@latest

bun add @langchain/langgraph@latest @langchain/core@latest

npmpnpmyarnbun

npm install @langchain/langgraph@latest @langchain/core@latest

Summary of changes

Area	What changed
React prebuilt	`createReactAgent` deprecated; use LangChain `createAgent`
Interrupts	Typed interrupts supported via `interrupts` config
`toLangGraphEventStream` removed	Use `graph.stream` with the desired `encoding` format
`useStream`	Supports custom transports

Deprecation: `createReactAgent` → `createAgent`

LangGraph v1 deprecates the createReactAgent prebuilt. Use LangChain's createAgent, which runs on LangGraph and adds a flexible middleware system.

See the LangChain v1 docs for details:

v1 (new)

v0 (old)

import { createAgent } from "langchain";

const agent = createAgent({
  model,
  tools,
  systemPrompt: "You are a helpful assistant.", // [!code highlight]
});

import { createReactAgent } from "@langchain/langgraph/prebuilts";

const agent = createReactAgent({
  model,
  tools,
  prompt: "You are a helpful assistant.", // [!code highlight]
});

v1 (new)v0 (old)

import { createAgent } from "langchain";

const agent = createAgent({
  model,
  tools,
  systemPrompt: "You are a helpful assistant.", // [!code highlight]
});

Typed interrupts

You can now define interrupt types at graph construction to strictly type the values passed to and received from interrupts.

v1 (new)

v0 (old)

import { StateGraph, interrupt } from "@langchain/langgraph";
import * as z from "zod";

const State = z.object({ foo: z.string() });

const graphConfig = {
  interrupts: {
    approve: interrupt<{ reason: string }, { messages: string[] }>(),
  },
}

const graph = new StateGraph(State, graphConfig)
  .addNode("node", async (state, runtime) => {
    const value = runtime.interrupt.approve({ reason: "review" }); // [!code highlight]
    return { foo: value };
  })
  .compile();

import { StateGraph } from "@langchain/langgraph";

const graph = new StateGraph(State)
  .addNode("node", async (state, runtime) => {
    const value = runtime.interrupt.approve({ reason: "review" }); // [!code highlight]
    return state;
  })
  .compile();

v1 (new)v0 (old)

import { StateGraph, interrupt } from "@langchain/langgraph";
import * as z from "zod";

const State = z.object({ foo: z.string() });

const graphConfig = {
  interrupts: {
    approve: interrupt<{ reason: string }, { messages: string[] }>(),
  },
}

const graph = new StateGraph(State, graphConfig)
  .addNode("node", async (state, runtime) => {
    const value = runtime.interrupt.approve({ reason: "review" }); // [!code highlight]
    return { foo: value };
  })
  .compile();

import { StateGraph } from "@langchain/langgraph";

const graph = new StateGraph(State)
  .addNode("node", async (state, runtime) => {
    const value = runtime.interrupt.approve({ reason: "review" }); // [!code highlight]
    return state;
  })
  .compile();

See Interrupts to learn more.

Event stream encoding

The low-level toLangGraphEventStream helper is removed. Streaming responses are handled by the SDK; when using low-level clients, select the wire format via an encoding option passed to graph.stream.

v1 (new)

v0 (old)

const stream = await graph.stream(input, {
  encoding: "text/event-stream",
  streamMode: ["values", "messages"],
});

return new Response(stream, {
  headers: { "Content-Type": "text/event-stream" }, // [!code highlight]
});

return toLangGraphEventStreamResponse({
  stream: graph.streamEvents(input, {
    version: "v2",
    streamMode: ["values", "messages"],
  }),
});

v1 (new)v0 (old)

const stream = await graph.stream(input, {
  encoding: "text/event-stream",
  streamMode: ["values", "messages"],
});

return new Response(stream, {
  headers: { "Content-Type": "text/event-stream" }, // [!code highlight]
});

Breaking changes

Dropped Node 18 support

All LangGraph packages now require Node.js 22 or higher. Node.js 18 reached end of life in March 2025.

New build outputs

Builds for all langgraph packages now use a bundler based approach instead of using raw typescript outputs. If you were importing files from the dist/ directory (which is not recommended), you will need to update your imports to use the new module system.

Summary of changes

Deprecation: createReactAgent → createAgent

Typed interrupts

Event stream encoding

Breaking changes

Dropped Node 18 support

New build outputs

Deprecation: `createReactAgent` → `createAgent`