Chat Bots & Bot Frameworks

Slack

• ★ @slack/bolt — official Slack app framework; events, slash commands, modals, app home, OAuth.
• @slack/web-api — lower-level client when you don't need the framework.
• @slack/socket-mode — for websocket apps that don't need a public URL.
• Slack Block Kit Builder — visual builder for message blocks.

Discord

• ★ discord.js — the standard; complete coverage of the Discord API.
• Discord.py (Python) — non-JS alternative.
• Sapphire Framework — opinionated framework on discord.js.
• @discordjs/voice — voice channels.

Telegram

• ★ grammY — modern TS-first; the default.
• telegraf — older but still used.
• node-telegram-bot-api — minimal API client.

WhatsApp / SMS

• Twilio SDK — SMS, MMS, WhatsApp Business; the default.
• MessageBird / Bird — alternative.
• Vonage (formerly Nexmo) — alternative.
• @whiskeysockets/baileys — unofficial WhatsApp Web library; reverse-engineered, against ToS for production.
• WhatsApp Cloud API (Meta) — official; requires Business verification.

Email-style bots

• Inbound email parsing: Postmark Inbound, SendGrid Inbound Parse, Resend (recently added inbound), CloudMailin, ImprovMX.
• See Email for sending.

SMS specifically

• Twilio Messaging — gold standard.
• Vonage, Plivo, Sinch — alternatives.
• AWS SNS — cheap, less ergonomic.
• MessageBird/Bird — global focus.

Voice / IVR

• Twilio Voice / Programmable Voice, SignalWire (Twilio fork; cheaper), Daily / LiveKit (see Realtime Video).
• AT&T <voice> clones — niche.

Microsoft Teams

• @microsoft/teamsfx — Teams Toolkit SDK.
• Bot Framework SDK (Microsoft) — for cross-Microsoft surfaces.

Patterns to know

• Idempotent webhooks — bots receive the same event twice; handle with a dedupe key.
• Rate limits — every platform has one; back off + queue.
• Slash command "ack within 3 seconds" — defer long work, post a follow-up message.
• OAuth flow per workspace / server — store tokens per install; rotate on re-install.
• Rich messages — Slack Block Kit, Discord embeds, Telegram inline keyboards. Don't send walls of text.

Where to host bots

• Cloudflare Workers — perfect for slash commands and webhooks. No cold start.
• Vercel — fine for webhook handlers; less great for long-running.
• Fly.io / Railway / Render — when you need a long-lived socket connection (Slack Socket Mode, Discord gateway).
• Inngest / Trigger.dev — for follow-up async work; see Workflow Engines.

Pick this if…

• Slack: @slack/bolt.
• Discord: discord.js.
• Telegram: grammY.
• SMS / WhatsApp: Twilio.
• Long-lived connections (Discord gateway): host on Fly / Railway, not serverless.
• Slack but no public URL needed: Socket Mode.