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Mailinator vs MailSlurp vs Mailosaur for AI agents

Three QA email tools, judged as inboxes for AI agents: the credential the agent holds, inbox privacy, code extraction, MCP support, and free tiers.

3 min read

On this page
  1. Side by side
  2. Mailinator
  3. MailSlurp
  4. Mailosaur
  5. Agent Temp Mail
  6. Verdict
  7. Sources

Mailinator, MailSlurp, and Mailosaur were built for QA teams testing their own apps’ email, and all three have since added features aimed at AI agents. But judged as an inbox for an agent rather than a test runner, different questions matter: what does the agent have to hold, can anyone else read its codes, how does it get the code out, and how does it connect over MCP?

Here’s how the three answer those questions, and how Agent Temp Mail, built for agents from the start, compares.

Side by side

Agent Temp MailMailinatorMailSlurpMailosaur
To get startedNothingNothing for public inboxesAccount and API keyAccount and API key
Private inboxYesPublic by defaultYesYes
Extracts codesYes, with contextLinks onlyRegex or paid AIYes
MCP serverLocal and hostedIn its CLIHostedNone official
Works in ChatGPTYes, no accountNoVia connectorNo
Address lifetimeNever expiresAny name; mail clears in hoursFree inboxes expirePersistent
PriceFreeFree public; $79 a month for businessFree tier; from $19.99 a monthTrial; from $20 a month

Filled dot: yes. Half dot: partly. Empty dot: no. From each vendor’s own pages, checked 10 October 2026.

Mailinator

Mailinator’s public system lets anyone use any address at mailinator.com without signing up, and its own documentation is blunt about the trade-off: public inboxes have no privacy, anyone can read or delete them, and mail clears after a few hours. Private domains, API access, and webhooks require an account, with business plans from $79 a month billed yearly.

Its official MCP server, inside mailinator-cli, offers two tools: list an inbox and read an email. On public inboxes that’s easy to try and unsafe for real sign-ins, since anyone who guesses the address sees the same codes. Mailinator’s own docs recommend private domains for codes and reset links.

MailSlurp

MailSlurp has gone furthest toward agents among the testing vendors: a hosted MCP server with OAuth or scoped agent keys, roles from read-only to responding, long-polling wait endpoints, and sending and SMS on paid plans. Code extraction is regex-based or a paid AI feature billed in tokens. You need an account and key, the free plan caps new inboxes at 100 a month, and free inboxes expire after a default time MailSlurp doesn’t publish.

Mailosaur

Mailosaur’s strength is extraction: every message arrives with detected codes and links, and its keys can be limited to a single inbox. But it has no official MCP server, so connecting it to an agent means a third-party wrapper holding your API key, and there’s no free tier beyond a 14-day trial, with plans from $20 a month billed yearly.

Agent Temp Mail: built for agents first

Each of the three asks an agent to work around a product designed for QA. Agent Temp Mail starts from the agent:

  • No account, no key to provision. The address comes from a key the agent generates, so a fresh, private inbox exists the moment it’s needed—for every agent, task, or test.
  • Private by construction. Signed reads; knowing the address isn’t enough.
  • Codes ready to use. Likely codes and verification links, extracted with context, on every message, at no extra cost.
  • Agent-native integrations. An official MCP server that signs outside the model, a Node.js SDK and CLI, function-tool definitions for the OpenAI and Anthropic APIs, and a read link ChatGPT can open with nothing installed.
  • Free. No trial clock and no per-inbox pricing.

Verdict

For AI agents

For agents that sign up, verify, and test, Agent Temp Mail is the simplest and safest choice: nothing to set up, private inboxes, codes extracted, and native MCP and ChatGPT support, free. If your QA team already runs on MailSlurp or Mailosaur, Agent Temp Mail slots in alongside them for agent work without another seat or API key.

Using it in tests? See testing email verification with Playwright. Comparing more widely? See 12 options compared.

Sources