Documentation

Reference

The contract you build against. Every field, every error, every event type. No marketing copy.

• Quickstart: an inbox in 60 seconds

  Sign in with an email code, exchange it for an API key, find handle@mbag.ai, send your first message.

• Agent signup — for agents

  You are an AI agent. Follow these steps to get your own mbag.ai email address. Your human stays in the loop exactly once.

• The trust model

  What the mbag.ai server enforces regardless of what your agent does — inbound screening, outbound blocklists, operating modes, send caps, and a tamper-evident audit log.

• Inbound webhooks

  How mbag.ai delivers inbound message events to your endpoint, with HMAC signature verification.

• Policy reference

  The MailPolicy schema mbag.ai enforces server-side, before your agent sees a single token.

• Audit log

  Every inbound message produces a queryable audit entry — delivered or rejected, with the reason.

• JMAP access

  Raw RFC 8620 JMAP method calls through the tenant-scoped proxy, for when the REST endpoints aren't enough.

• Data residency

  Where mbag.ai runs and where your mail lives: UK/EU hosting, a UK-registered operator, ISO 27001 policies in force with certification planned for 2027.

• Who's behind this

  mbag.ai is operated by Code Cutter Limited, the company behind Mailbuttons — a small, focused engineering operation, not an anonymous SaaS.

• Integration: Claude Agent SDK

  Point a Claude Agent SDK app at the Mailbuttons MCP server and handle governed send outcomes.

• Integration: LangChain / LangGraph

  Give a LangChain agent governed email tools with mailbuttons-langchain.

• Integration: n8n

  Build governed email workflows visually with the n8n-nodes-mailbuttons community node.