WhatsApp is where your customers already are, and Waxum is the self-hosted gateway that lets your own software talk to them there without renting a per-message platform. One REST API fronts two providers at once: multi-device sessions paired by QR code or pairing code, and Meta's official Cloud API, sharing the same message routes and webhook events. Send text, media, locations, contact cards, polls, reactions, and broadcast lists, schedule messages for later, or run paced bulk blasts with deduplication, retries, and a dead-letter queue when a send fails. Voice and video calls ring, play audio, speak text in hundreds of voices, record the peer side, and stream media over WebSocket, while groups, contacts, blocking, privacy settings, and presence are all manageable per session. Signed webhooks with event filters and circuit breakers push receipts and replies into your app, and a failed delivery can be replayed from the queue instead of lost. The built-in ops console shows your whole session fleet, and each session opens a playground covering dozens of endpoints, so you can test a send from the browser before writing code. Sessions export and import between instances as zip files, and Prometheus metrics with health probes keep the fleet observable. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.