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
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