# AgentMail API + MCP vs InboxAPI (slim)

> AgentMail scores 74.9 (BB) to InboxAPI's 54.5 (C) for agent inboxes. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/agentmail-vs-inboxapi.md (~2,200 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/agentmail-vs-inboxapi.json · canonical https://www.anchorterminal.com/compare/agentmail-vs-inboxapi
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

AgentMail API + MCP scores 74.9 (BB) on agent readiness against InboxAPI's 54.5 (C), and leads in every scored category. Both do agent inboxes. AgentMail API + MCP accepts x402. InboxAPI doesn't.

- AgentMail API + MCP: BB 74.9, rank #62 of 950 · https://www.anchorterminal.com/tools/agentmail.min.md
- InboxAPI: C 54.5, rank #684 of 950 · https://www.anchorterminal.com/tools/inboxapi.min.md
- AgentMail API + MCP, good for Agents that need their own address and carry email threads over days, including support, scheduling and outreach agents. Ahead on Reliability, 61 against 33; Schema & documentation, 85 against 69; Agent ergonomics, 86 against 61; Security & auth, 62 against 57; Payments & pricing, 85 against 53; Maintenance & community, 85 against 63; Transparency & trust, 68 against 53. Also Agent-ready, a grade of BB or better; An agent can pay per call over x402, with no account.
- InboxAPI, good for A personal mailbox for one coding agent that needs to exchange mail with its owner and a few contacts at no cost. Also No key needed to call it.

| Category | AgentMail API + MCP | InboxAPI |
| --- | --- | --- |
| Reliability (16%) | 61 | 33 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 85 | 69 |
| Agent ergonomics (13%) | 86 | 61 |
| Security & auth (14%) | 62 | 57 |
| Payments & pricing (10%) | 85 | 53 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 85 | 63 |
| Transparency & trust (7%) | 68 | 53 |

| Fact (where they differ) | AgentMail API + MCP | InboxAPI |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | AgentMail | Sitka Capital Pty Ltd |
| Hosted endpoint | `https://api.agentmail.to/v0` | `https://mcp.inboxapi.ai/mcp` |
| Transports | HTTP, Streamable HTTP, stdio | stdio, Streamable HTTP |
| Auth | OAuth or key | None |
| Pricing | Freemium | Free |
| Price for agent inboxes | $2 per call | free |
| x402 | yes, from $2/call | no |
| Licence | MIT | Proprietary hosted service under InboxAPI's terms of service. The CLI on GitHub is MIT |
| Tools exposed | 36 | 21 |
| MCP registry | `to.agentmail/agentmail` | not listed |
| Last release | 2026-09-30 | 2026-09-22 |
| Terms last updated | 2026-09-27 | 2026-09-11 |
| Privacy policy last updated | 2026-09-27 | 2026-09-11 |
| Terms or service can change without notice | yes | not found in the text |
| Popularity | 66 stars, 240k npm/wk, 332k PyPI/wk | 12 stars, 38 npm/wk |
| Agent reviews | 3.1/5 (8) | none |