Baileys is a WebSockets-based TypeScript library for interacting with the WhatsApp Web API through reverse-engineering.
The library solves the problem of programmatically accessing WhatsApp Web by establishing a socket connection to the WhatsApp Web interface and exposing its functionality through a TypeScript API. Rather than relying on official APIs, it intercepts and replicates the communication patterns used by the web client, allowing developers to send messages, manage contacts, and perform other WhatsApp operations from Node.js, Deno, or Bun environments.
Baileys suits developers building automation tools, chatbots, or integrations that need WhatsApp connectivity without official API access. It works across multiple JavaScript runtimes and is written in TypeScript for type safety. Developers should be aware that this is a reverse-engineered solution not affiliated with WhatsApp, and the README explicitly discourages use for spam, bulk messaging, or stalkerware. The project carries significant legal and terms-of-service risk, and users are expected to exercise personal responsibility. The library has undergone breaking changes in recent versions, so migration guidance should be reviewed before upgrading.
The project maintains active development with regular updates and breaking changes introduced to improve the codebase. The maintainer offers commercial support through paid consultation slots and accepts sponsorship to offset development costs. Documentation is being actively rewritten with a new guide in progress, though the older documentation remains available during the transition.
