Guides & engineering notes

WhatsApp for AI agents and phone systems

Step-by-step guides to connect WhatsApp to Claude, ChatGPT, Cursor, Grok and your PBX, plus the engineering behind it: SIP bridging, the MLow voice codec, webhooks and per-number egress.

Schematic diagram of Opus and G.711 waveforms converging into a transcoder node, in the Terminal Noir style.
Configuration Oct 2, 2026 · 4 min read

PJSIP Settings for a WhatsApp SIP Bridge

The pjsip.conf settings that matter for the WhatsMCP bridge: G.722/G.711 codec order, endpoint vs trunk, NAT, one call per number, and what doesn't cross.

By WhatsMCP Engineering Read post
Connect Asterisk to WhatsApp with a QR Code
SIP Trunking Oct 1, 2026 · 11 min read

Connect Asterisk to WhatsApp with a QR Code

Step-by-step: link WhatsApp by QR code, then connect Asterisk PJSIP so WhatsApp calls ring your phones and your users dial WhatsApp numbers.

By WhatsMCP Engineering Read post
WhatsApp Message Templates Meta Approves
Configuration Sep 25, 2026 · 8 min read

WhatsApp Message Templates Meta Approves

How WhatsApp Business API templates work: categories, variables, limits, common rejection reasons, 10 examples, and sending them from an AI agent.

By WhatsMCP Engineering Read post
The MLow codec in pure Go — a clean-room encoder and decoder for Meta's low-bitrate voice codec. WhatsMCP Engineering.
Audio Codecs Sep 11, 2026 · 13 min read

Rebuilding MLow: WhatsApp's Voice Codec in Pure Go

How we built a clean-room, pure-Go encoder and decoder for MLow — Meta's low-bitrate codec behind billions of WhatsApp, Messenger and Instagram calls: the hybrid SILK/CELT structure, reverse-engineering it against the live library, and frame-exact validation.

By WhatsMCP Engineering Read post
Bridging WhatsApp and the PBX — a low-latency SIP trunking bridge. WhatsMCP Engineering.
SIP Trunking Sep 11, 2026 · 12 min read

Bridging WhatsApp and PBX: Low-Latency SIP Trunking Internals

A deep technical tour of the real-time transcoding bridge that connects WhatsApp calls to Asterisk and FreeSWITCH: dual-plane signaling, Opus/G.711 transcoding, jitter buffering, PLC, a sub-50 ms media path, and the war stories behind each decision.

By WhatsMCP Engineering Read post