# InboxAPI

> Your AI agent's personal email. Give your AI agent its own personal email address.

InboxAPI lets AI agents send, receive, search, reply to, and forward email via the Model Context Protocol (MCP). It works with Claude, Gemini, Codex, OpenCode, and any MCP-compatible client.

## Install

npm install -g @inboxapi/cli@latest

## Connect

Claude Code:
  claude mcp add inboxapi inboxapi

Claude Code (global):
  claude mcp add inboxapi inboxapi -s user

Gemini CLI:
  gemini mcp add inboxapi inboxapi --scope user

OpenCode:
  opencode mcp add

Codex CLI:
  codex mcp add inboxapi inboxapi

## Key Facts

- Not a Gmail/Outlook replacement — agents should have their own personal email identity, not access to your personal inbox. Separate inbox means no access to your private emails, no sending as you, no OAuth middleware needed.
- Free to use. No credit card, no usage tiers.
- Not a wrapper around SES, SendGrid, or Postfix — we built and operate the entire email stack.
- Each agent gets a unique, personal @inboxapi.ai email address automatically.
- Full email capabilities: send, receive, search, reply, forward, thread tracking.
- Built-in abuse prevention: proof-of-work signup, recipient caps, send quotas, rate limiting.
- Email trust classification on every inbound message (trusted, agent, unverified, suspicious).
- Credential leak prevention: outbound emails containing tokens are automatically rejected.
- SPF, DKIM, and DMARC configured automatically.
- Why email instead of messaging apps? Email offers scalability (programmatic address creation), no gatekeeping (no phone or platform approval), open protocol (federated, vendor-neutral), ToS compliance (messaging platforms prohibit automated accounts; email doesn't), and universal reach (not siloed like WhatsApp/Telegram/Discord).
- Owner verification: link your personal email to your agent's account via verify_owner, then use account_recover to restore access if credentials are ever lost.
- Recommended models: any model with tool/function calling and 32K+ context window. Works well with Claude Haiku 4.5+, GPT-4.1 mini+, Gemini 2.5 Flash+ and above. Datamarking on untrusted emails may increase token usage.

## Comparison

InboxAPI vs other email services for AI agents:

- AgentMail: Similar agent-focused product. Has semantic search, multiple inboxes, custom domains. Does not disclose infrastructure. Paid plans from $20/mo.
- a1base (A1Mail): Multi-channel (email + WhatsApp + SMS + phone). Email product is in alpha. No MCP support.
- Resend, Postmark, Mailgun: Transactional sending APIs. No native inbox, no thread management, no agent identity. Require building your own infrastructure on top.

InboxAPI is the only service that combines: own email infrastructure (not a wrapper), MCP-native integration, prompt injection defense (trust classification + datamarking), credential leak prevention, and completely free usage.

## Insights & Guides

- Inbound Mail Processing: https://inboxapi.ai/insights/inbound-mail-processing/ - Guide on receiving, MIME parsing, and handling incoming emails.
- Inbound Mail Tracking Systems: https://inboxapi.ai/insights/inbound-mail-tracking-system/ - Auditing and tracking incoming messages.
- Inbound Mail Solutions: https://inboxapi.ai/insights/inbound-mail-solutions/ - Comparing self-hosted MTAs vs. managed email APIs.
- What is Inbound Email: https://inboxapi.ai/insights/inbound-email/ - Introduction to inbound email routing and email inbound processing.
- Best Email API for Developers: https://inboxapi.ai/insights/best-email-api-for-developers/ - Comparison of SendGrid, Resend, AWS SES, and InboxAPI.
- Best Free Email API: https://inboxapi.ai/insights/best-free-email-api/ - Reviewing free tiers and domain requirements for developer APIs.
- Demystifying Email Deliverability: https://inboxapi.ai/insights/deliverability-demystified/ - Explain SPF, DKIM, DMARC, and alignment.

## Links

- Website: https://inboxapi.ai
- Docs: https://inboxapi.ai/getting-started/
- npm: https://www.npmjs.com/package/@inboxapi/cli
- GitHub: https://github.com/inboxapi/cli