MailTester Email Verification — Claude Code MCP Server
Remote email verification server for AI coding assistants. It checks inbox deliverability and flags risky or disposable addresses before sending messages.
claude mcp add --transport http email-verification https://app.mailtester.com/mcpWhat MailTester Email Verification does
This remote service connects over streamable HTTP at https://app.mailtester.com/mcp. Because it runs in the cloud, you do not need to download or install local packages to use it.
The tool exposes verify_email for individual checks and verify_batch for lists of up to 25 contacts at a time. The agent receives definitive verdicts: valid, invalid, risky, or unknown. Additional functions include explain_result for deliverability advice and get_api_key to generate credentials directly inside the chat.
Free agent keys grant 25 verifications per day and expire after 30 days. Reaching the ceiling or exceeding 10 requests per minute triggers an HTTP 429 response until 00:00 UTC.
What it helps with
- verify whether an address exists before dispatching messages
- filter out temporary inboxes and catch-all domains
- validate batches of up to 25 email addresses
- inspect deliverability recommendations for uncertain addresses
Example prompts for the agent
- Verify the address [email protected] and explain the result
- Run verify_batch on the list of contacts in subscribers.csv
- Check the remaining daily verification balance with get_credit_balance
How to install MailTester Email Verification
Platform CLI: remote server
claude mcp add --transport http email-verification https://app.mailtester.com/mcpPlatform CLI: remote server
codex mcp add mailtester-email-verification --url https://app.mailtester.com/mcpConfig file
{
"mcpServers": {
"mailtester-email-verification": {
"url": "https://app.mailtester.com/mcp"
}
}
}Config file
{
"servers": {
"mailtester-email-verification": {
"type": "http",
"url": "https://app.mailtester.com/mcp"
}
}
}Platform CLI: remote server
gemini mcp add -t http mailtester-email-verification https://app.mailtester.com/mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about MailTester Email Verification
How do I install MailTester Email Verification in Claude Code?
Add the remote endpoint by running claude mcp add --transport http mailtester-email-verification https://app.mailtester.com/mcp. If you have a token, include it via the authorization header option.
What does MailTester Email Verification do?
It queries remote mail servers to determine whether an email address actually accepts incoming mail. The server categorizes each lookup as valid, invalid, risky, or unknown.
What limits apply to free agent keys?
Each free key includes 25 checks per day and remains active for 30 days. Traffic is limited to 10 requests per minute with a single active request at a time.
