Introduction

Chat SDK is a TypeScript library for building chat bots that run on multiple platforms from one codebase. You write the bot logic once and deploy it to any platform that has an adapter.

Why Chat SDK?

Each chat platform has its own API, webhook format, and quirks, so supporting several of them usually means maintaining separate code for each. Chat SDK puts those differences behind adapters and gives you one interface for:

• Typed event handlers for mentions, messages, reactions, button clicks, slash commands, and modals
• Thread subscriptions for multi-turn conversations
• Cards, buttons, and modals written in JSX that render natively on each platform
• Streaming LLM responses into a message
• Serverless deployments, with distributed state in Redis and message deduplication

How it works

Chat SDK has three core concepts:

1. Chat coordinates your adapters and routes incoming events to your handlers.
2. Adapters handle the platform-specific work: parsing webhooks, formatting messages, and calling the platform's API.
3. State is a pluggable persistence layer for thread subscriptions and distributed locking.

import { Chat } from "chat";
import { createSlackAdapter } from "@chat-adapter/slack";
import { createRedisState } from "@chat-adapter/state-redis";

const bot = new Chat({
  userName: "mybot",
  adapters: {
    slack: createSlackAdapter(),
  },
  state: createRedisState(),
});

bot.onNewMention(async (thread) => {
  await thread.subscribe();
  await thread.post("Hello! I'm listening to this thread.");
});

Adapter and state factories read their credentials from environment variables such as SLACK_BOT_TOKEN, SLACK_SIGNING_SECRET, and REDIS_URL, so the example above passes no options. Pass explicit values to override them.

Adapters

Install only the adapters you need. Browse the full catalog on the Adapters page, and compare official platform features on Platform Adapters.

AI coding agents

If you use an AI coding agent such as OpenAI Codex, Claude Code, or Cursor, install the Chat SDK skill so it knows the SDK's APIs, adapter patterns, and project conventions before it writes code.

npx skills add vercel/chat

The skill references bundled documentation in node_modules/chat/docs, plus adapter guides and starter templates in the published package.

You can also install the Vercel Plugin for a broader agent toolkit. It includes the Chat SDK skill along with specialist agents and slash commands:

npx plugins add vercel/vercel-plugin

For agent-readable documentation, see llms.txt (page index) or llms-full.txt (full text).

Contributing

Ship an adapter for a new platform, or list a vendor-maintained one in the catalog.