Developer Builds WhatsApp Business MCP Server with Claude Code in Single Session
A developer built a complete WhatsApp Business MCP server using Claude Code in a single coding session. The server connects Claude with the WhatsApp Business API, allowing users to ask Claude to send WhatsApp messages and have it execute those commands.
Technical Implementation
The project was built with the following architecture and features:
- Architecture: Cloudflare Workers + D1 + KV + Durable Objects
- Tool handlers: 35 tool handlers with Zod validation
- Testing: 72 unit and integration tests
- Billing system: Lemonsqueezy webhooks and API key generation
- Multi-tenant support: Each user gets their own WhatsApp credentials
- Security audit: Multiple parallel agents found and fixed 16 vulnerabilities
- Deployment: Direct deployment to Cloudflare Workers from terminal
Server Capabilities
The MCP server includes 8 modules:
- Messages
- Interactive buttons/lists
- Templates
- Media
- Webhooks (receive messages)
- Business profile
- WhatsApp Flows
- Analytics
The webhook module is unique — no other WhatsApp MCP server can actually receive incoming messages.
Technical Details
- TypeScript strict mode
- 72 tests passing
- Timing-safe HMAC for webhook verification
- SSRF protection on media uploads
- Tenant isolation via separate Durable Object instances
- Rate limiting per API key
The project is free to try with 5 tools and no API key required. The developer notes they're happy to answer questions about building MCP servers with Claude Code.
📖 Read the full source: r/ClaudeAI
👀 See Also
A TDD Development Flow Using AI Agents for Website Projects
A developer shares their workflow for building websites using AI coding agents with TDD, detailing setup steps, iterative processes, and specific commands for running tests with local models like Qwen3.5-27B.
Developer Compares Claude AI to a Modern Calculator for Coding Workflow
A developer with 18 months on a serverless Angular/AWS SPA/PWA project reports using Claude AI for 90% of AI-assisted coding, describing it as a '21st century version of a calculator' that makes them 10x more productive despite occasional catastrophic outputs.
Using Claude with MCPs for Automated B2B Outbound Campaigns
A Reddit user shares their workflow using Claude with Model Context Protocol (MCP) servers to automate B2B outbound campaigns, replacing Clay with custom API integrations for lead discovery, enrichment, verification, and email sending.
OpenClaw's Bub AI agent struggles with delegation, burns $20 in 15 minutes during mobile site optimization
During QA for Driftwatch V3, the OpenClaw bot Bub burned $20 in 15 minutes by failing to delegate tasks properly. The developer discovered detailed spec templates reduce costs, while mobile retrofitting added unexpected time and expense.