API Documentation
Agent Mailbox Platform

Agent Mailbox API Reference

Build AI-powered email workflows with our APIs. Send emails, receive messages, manage mailboxes, and track analytics programmatically.

https://api.agentmail.compostable.ai

Portal API

JWT + HMAC

Self-service API for managing your email infrastructure. Create subdomains, configure mailboxes, generate API credentials, and monitor usage. Supports both web portal (JWT) and programmatic (HMAC) access.

Mailbox API (System)

HMAC-SHA256

Core API for AI agents and automated systems. Send emails, retrieve messages, manage attachments, and track usage. All operations authenticated via HMAC signatures.