Chat SDK is a TypeScript library for building chat bots that work across multiple platforms with a single codebase. Write your bot logic once and deploy it to Slack, Microsoft Teams, Google Chat, Discord, Telegram, GitHub, Linear, WhatsApp, and Messenger.

Building a chat bot that works across multiple platforms typically means maintaining separate codebases, learning different APIs, and handling platform-specific quirks individually. Chat SDK abstracts these differences behind a unified interface.

• Single codebase for all platforms
• Type-safe adapters and event handlers with full TypeScript support
• Event-driven architecture with handlers for mentions, messages, reactions, button clicks, slash commands, and modals
• Thread subscriptions for multi-turn conversations
• Rich UI with JSX cards, buttons, and modals that render natively on each platform
• AI streaming with first-class support for streaming LLM responses
• Serverless-ready with distributed state via Redis and message deduplication

Chat SDK has three core concepts:

1. Chat — the main entry point that coordinates adapters and routes events to your handlers
2. Adapters — platform-specific implementations that handle webhook parsing, message formatting, and API calls
3. State — 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.");
});

Each adapter factory auto-detects credentials from environment variables (SLACK_BOT_TOKEN, SLACK_SIGNING_SECRET, REDIS_URL, etc.), so you can get started with zero config. Pass explicit values to override.

If you use an AI coding agent like Claude Code, you can teach it about Chat SDK by installing the skill:

npx skills add vercel/chat

This gives your agent access to Chat SDK's documentation, patterns, and best practices so it can help you build bots more effectively.

The SDK is distributed as a set of packages you install based on your needs: