Compare

Agentmail vs Mailgun

Agentmail scores higher on the AgentReady, 84/100 against 58/100. They differ on 14 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Agentmail. AgentMail is an email inbox API for AI agents.

Mailgun. Transactional Email Delivery Service & API for Developers.

Where Agentmail is ahead

Agentmail passes public docs discoverable, llms.txt published and llms-full.txt / full agent docs, and Mailgun does not. That is discover, whether an agent can find the product at all without being told it exists.

It also holds understand: structured api reference, openapi / spec quality, request examples provided, response examples provided and errors and status codes documented. Mailgun misses those.

And on adopt, programmatic credential creation and cli available. Mailgun misses those.

Finally, on operate, structured, predictable output and machine-readable errors. Mailgun misses those.

Where Mailgun is ahead

Mailgun passes search discoverable, and Agentmail does not. That is discover, whether an agent can find the product at all without being told it exists.

It also holds adopt: agent-compatible signup flow. Agentmail misses it.

What neither does

Both fail limits / constraints documented, no mandatory sales call, retry behavior documented, idempotency support, rate-limit behavior predictable. If your agent needs any of those, you will be building it yourself either way.

Score, pillar by pillar

The AgentReady splits into four pillars, scored separately, because a product can be easy to find and still impossible to adopt.

Discover. Agentmail leads 87 to 73. Agentmail misses search discoverable; Mailgun misses public docs discoverable, llms.txt published, llms-full.txt / full agent docs.

Understand is whether an agent can read the docs and work out how the API behaves before calling it. Agentmail leads 92 to 31. Agentmail misses limits / constraints documented; Mailgun misses structured api reference, openapi / spec quality, request examples provided, response examples provided, errors and status codes documented, limits / constraints documented.

Adopt. Agentmail leads 80 to 75. Agentmail misses no mandatory sales call, agent-compatible signup flow; Mailgun misses no mandatory sales call, programmatic credential creation, cli available.

Operate. Agentmail leads 76 to 53. Agentmail misses retry behavior documented, idempotency support, rate-limit behavior predictable; Mailgun misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable.

Pricing

Agentmail starts at $0/mo and has a free tier. Mailgun does not publish one and has a free tier.

Signal by signal

Which to pick

Agentmail clears more of the signals an agent needs, so it is the safer default for unattended use. Full profiles: Agentmail and Mailgun. Alternatives to each: Agentmail, Mailgun.

An agent can fetch this as data: POST /v1/compare {"slugs": ["agentmail", "mailgun"]}