MCP.Market

MailTester Email Verification MCP server

online · 96% uptime
by mailtester.com·com.mailtester/email-verification·v1.0.1
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Verify emails (valid/invalid/risky/unknown): MX, SMTP, catch-all, disposable. Free agent key.

B84/100grade B
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Safety scan
B84/100

full report

Adoption
Growing

0 stars

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If you have run it, two minutes of your experience saves the next person an afternoon.

MailTester Email Verification tools (9, 1 write)

write = sends, deletes, buys or posts
  • estimate_costFree

    Estimate the credit cost of a verification before running it, and whether the user can afford it. Provide either a count of emails, a list_id to re-verify, or an operation ('single'/'finder'). Always quote this before proposing anything billable.

  • explain_resultFree

    Explain what a verification status or reason means in plain English, with a send recommendation. Covers valid, invalid, catch-all/accept-all, unknown, greylisted, disposable, role, free, spam-trap, abuse, do-not-mail, no-mx, disabled, and network. Use when a user asks what a result means.

  • get_api_keyFree

    Get a free API key for this server (no account needed; 25 email verifications per day). Returns the key once — reconnect with 'Authorization: Bearer <api_key>' to use the other tools.

  • get_batch_statusFree

    Get the progress and status of a bulk verification list/job by id.

  • get_credit_balanceFree

    Get the current credit balance and a short usage summary for the account.

  • get_listFree

    Get the details of a single bulk verification list by its id.

  • list_listsFree

    List the user's bulk verification lists/jobs, most recent first.

  • verify_batchFree

    Verify a batch of email addresses (up to 25 per call with an agent key). Returns per-email verdicts and saves a list. Costs 1 credit per email.

  • verify_emailwrite actionFree

    Verify the deliverability of a single email address. Returns a verdict (valid, invalid, risky, unknown). Costs 1 credit.

Public scan report

scanner v0.1.10 · 2026-10-09 · same rubric, same numbers if you re-run it

no findings
  • –Code scanremote-only server, no package to scann/a
  • Live reliabilityremote reachable in 2134ms17/20
  • Tool poisoning9 tool descriptions checked15/15
  • Auth qualityAPI key sent as a header8/15
  • Maintenancelast push 1 days ago15/15
  • Maintainer identitynamespace and repository owner differ; GitHub account older than a year; website matches verified namespace8/10
Overall 84/100. Components that don't apply are left out of the denominator. Any critical finding is an F.RubricAppeal a findingJSON

How MailTester Email Verification compares

Against every graded Email MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score
84/100
higher than 76% of 916 Email servers
Tools
9
the typical Email server has 7
Tools that change things
11%
typical: 25%. Fewer write tools means less an agent can break
Uptime
96%
of our recent checks; the typical remote Email server answers 100%
Response time
408 ms
faster than 37% of 609 Email servers

What its tools let an agent do: 8 read · 1 change

Install MailTester Email Verification in Claude Code, Cursor or VS Code

claude mcp add --transport http email-verification https://app.mailtester.com/mcp
Add to Cursor

What the publisher says

From the MailTester Email Verification repository's README, as published. We do not edit it. Read it on GitHub

MailTester MCP server — email verification for AI agents

Remote Model Context Protocol server that tells an AI agent whether an email address can receive mail before anything is sent to it.

  • Endpoint: https://app.mailtester.com/mcp (Streamable HTTP, JSON responses)
  • Official MCP Registry: com.mailtester/email-verification
  • Website: https://mailtester.com
  • Agent docs: https://app.mailtester.com/agent-gateway · OpenAPI · llms.txt · agent card

The server is hosted; there is nothing to install. This repository documents how to connect.

Get a key (no account needed)

Connect without a key and call the getapikey tool, or:

curl -X POST https://app.mailtester.com/agent-gateway/register \
  -H 'Content-Type: application/json' \
  -d '{"name":"my-agent","purpose":"verify signup emails"}'

The key is shown once. Each key gets 25 free verifications per day (unused credits do not roll over) and expires after 30 days; register again when it does. Send it as Authorization: Bearer .

Connect

Claude Code

claude mcp add --transport http mailtester https://app.mailtester.com/mcp --header "Authorization: Bearer YOUR_KEY"

Claude Desktop / Cursor / VS Code (mcp.json-style config)

{
  "mcpServers": {
    "mailtester": {
      "type": "http",
      "url": "https://app.mailtester.com/mcp",
      "headers": { "Authorization": "Bearer YOUR_KEY" }
    }
  }
}

Tools

Verdicts

  • valid: the mailbox exists and accepts mail
  • invalid: the address or domain cannot receive mail
  • risky: accept-all (catch-all) domain, role or disposable address, or a Microsoft 365 address the mail server couldn't confirm
  • unknown: the receiving server gave no definitive answer

Limits

10 requests per minute per key, one request in flight per key, and a shared daily capacity for free agent keys (HTTP 429 until 00:00 UTC when it is used up). Inbox placement, blacklist monitoring and email finder need a full account at https://mailtester.com.

REST API

The same key works on the REST API: POST https://app.mailtester.com/api/v1/verify, POST https://app.mailtester.com/api/v1/verify/batch, GET https://app.mailtester.com/api/v1/credits. See the OpenAPI description.

Nothing above is checked by us. What we check is on the safety report.

MailTester Email Verification: common questions

Is MailTester Email Verification MCP server safe?
Mostly: it is graded B (84/100). Read the MailTester Email Verification safety report
How do I install MailTester Email Verification?
It runs remotely at app.mailtester.com. Add it to Claude Code, Cursor, VS Code or Claude Desktop with the snippets above, or call it through the mcp.market gateway without installing anything.
Does MailTester Email Verification need an API key?
Yes. The registry entry asks for Authorization.
Is MailTester Email Verification maintained?
The last commit was 26 days ago (2026-10-08). The latest release is v1.0.1.
Is MailTester Email Verification up?
96% of our last 28 checks got an answer. We check remote servers about four times a day.
What can I use instead of MailTester Email Verification?
Servers from other publishers that do the same job: MailProbe MCP server, Forward Email MCP server and smails MCP server.
How does MailTester Email Verification compare with other Email MCP servers?
safety score 84/100 (higher than 76% of 916 Email servers); tools 9 (the typical Email server has 7); tools that change things 11% (typical: 25%. Fewer write tools means less an agent can break). Full comparison.

Alternatives to MailTester Email Verification

Same job from other publishers: the closest match first, then the best rated.

  • MailProbe
    Verify email addresses in real time: deliverability, disposable and role addresses, typo fixes.
    A
  • Forward Email
    Privacy-focused email: domains, DNS verification, aliases, SMTP sending, mailboxes and calendars.
    A
  • smails
    Free disposable email for AI agents: a throwaway inbox to read verification codes over MCP.
    B
  • EmptyInbox
    Zero-config disposable email inboxes for AI agents: create, read mail, await verify codes.
    B
  • Mailoo - Email MCP Server
    Email MCP server for AI agents: IMAP/SMTP, Gmail, Outlook, calendar, ManageSieve, AI triage, OAuth2.
    A