Free MCP Server for AI Agents — Temporary Email Inboxes

The Temp Mail Agency MCP server gives any AI agent a working email inbox in one tool call. Agents use it to sign up for services, receive confirmation links and read verification (OTP) codes — without a human mailbox. It is free: sign in with Google once on the API access page to get an API key with 100 emails/day. It is the same free, receive-only temporary email service as the temp-mail.agency website, exposed over the Model Context Protocol.

POST https://temp-mail.agency/mcp

Streamable HTTP transport · JSON-RPC · Free API key (Google sign-in) · 100 emails/day

First: get your free API key

The MCP server is free — it just needs a key so your 100 emails/day are yours. One click with Google, no card, no forms.

Sign up with Google — get my key

Quick start

Step 1: Get your free API key — one click with Google sign-in. Keys include 100 emails/day across the MCP server and the REST API combined.

Step 2: Add the server to your MCP client. In Claude Code:

claude mcp add --transport http temp-mail https://temp-mail.agency/mcp --header "Authorization: Bearer YOUR_API_KEY"

In Claude Desktop, Cursor, Windsurf or any client that takes a server URL and headers:

{"mcpServers": {"temp-mail": {"url": "https://temp-mail.agency/mcp", "headers": {"Authorization": "Bearer YOUR_API_KEY"}}}}

Or test it with a single request:

curl -X POST https://temp-mail.agency/mcp \ -H "Content-Type: application/json" \ -H "Authorization: Bearer YOUR_API_KEY" \ -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"create_inbox","arguments":{}}}'

How agents use it

  1. create_inbox — the agent gets a fresh address (for example [email protected]) plus a private inbox_id.
  2. Use the address — the agent registers or requests a verification email on the target service.
  3. get_verification_code — the agent pulls the OTP/confirmation code straight out of the arriving email, or reads the full message (including links) with get_messages.
  4. delete_inbox — the agent cleans up when the task is finished.

Tools

create_inbox

Create a free disposable inbox. Optional alias for a custom name and domain_id to pick a domain. Returns the address and its private inbox_id.

get_messages

Read an inbox: sender, subject, date, plain-text body, any verification code detected, and the links inside each message.

get_verification_code

Return just the newest OTP / confirmation code in the inbox — the fastest path through sign-up flows.

list_domains

List the domains currently available for new inboxes, with the ids create_inbox accepts.

delete_inbox

Permanently delete an inbox and its address when the task is done.

Why agents use disposable inboxes

  • Sign-ups and trials — register for services without burning a real mailbox.
  • Verification codes — OTP extraction is a built-in tool, not an afterthought.
  • QA and end-to-end testing — assert that signup, password-reset and invite emails actually arrive.
  • Privacy — keep agent activity out of a human's personal inbox.

Honest limits

Receive-only: agents cannot send email from these inboxes. Addresses are disposable, so some websites may reject them. Free keys include 100 emails/day (inbox creations, messages read and code fetches), shared across MCP and API, plus fair-use rate limits per network. For persistent two-way agent mailboxes with custom domains, a paid provider such as AgentMail fits better — see the honest comparison.

FAQ

Is the Temp Mail Agency MCP server really free?

Yes. The MCP server is completely free: no plans and no credit card. You sign in once with Google to get a free API key, and the key includes 100 emails/day — one email being an inbox created, a message read, or a verification-code fetch — shared across the MCP server and the REST API. The allowance resets at midnight UTC.

Which AI clients can use this MCP server?

Any client that supports the Model Context Protocol over Streamable HTTP — including Claude, Claude Code, Cursor, Windsurf and custom agents built on MCP SDKs. The endpoint speaks standard JSON-RPC, so generic MCP tooling works too.

Can an AI agent send email through this MCP server?

No. Temp Mail Agency inboxes are receive-only by design: they exist so agents can receive sign-ups, confirmation links and verification codes without exposing a real mailbox. There is deliberately no send tool.

How long does an MCP inbox last?

The address stays active until you delete it with delete_inbox — there is no 10-minute or 1-hour countdown. It is built for sign-up and verification flows that can take a while. Messages are for short-term use, so read what you need promptly.

Is an MCP inbox private?

Yes. Reading an inbox requires its inbox_id, a token returned only when the inbox is created. Anyone holding that token can read the inbox, so agents should treat it like a password and delete the inbox when the task is done.

What happens if a website rejects disposable domains?

Some services block known disposable domains. Temp Mail Agency offers several domains, and new ones rotate in over time. If one domain is rejected, create a new inbox on a different domain with list_domains and create_inbox.