Introduction

WA Gateway is a multi-tenant WhatsApp gateway built on whatsapp-web.js. You create apps. Each app is linked to its own WhatsApp account by QR code and gets:

• a REST API protected by a per-app API key,
• an optional webhook URL that receives incoming messages and delivery receipts,
• its own message log and rate limit.

How it fits together

your backend ──x-api-key──▶  WA Gateway  ──▶  headless Chromium (one per app)  ──▶  WhatsApp
your backend ◀──signed webhook──  WA Gateway

Each app runs its own headless Chromium session, so the gateway is sized by how many numbers you link (plan about 1 to 1.2 GB of RAM per number). Logins and data live in PostgreSQL, so the server itself is disposable.

Which API do I need?

You are...	Use	Header
Sending and receiving messages for one number	Tenant API	x-api-key
Operating the gateway (create apps, restart, clean up)	Admin API	x-admin-key or dashboard session
A product that creates WhatsApp apps for its own customers	Provisioning API	x-provisioning-key

Unofficial API

whatsapp-web.js automates WhatsApp Web. It is not the WhatsApp Business Platform, and WhatsApp can restrict numbers that send spam. Message only people who expect to hear from you.