# Mails.so — MCP server on mcp.ai
> Connect your Mails.so account and use 3 tools for email straight from your AI agent. Connect with your own API key. Mails is an API service that provides powerful email validation capabilities to help maintain a clean and effective email list.

By: mcp.ai · official
Page: https://mcp.ai/mails_so

## Connect (MCP protocol)
Remote MCP endpoint (HTTP, streamable): https://api.mcp.ai/p_mails_so?ms=1787291220000
Add it as a custom/remote MCP connector, then authenticate when prompted.

## REST API (no MCP client required)
Every tool is also a REST endpoint, authed with a workspace API key.
Discover: GET https://api.mcp.ai/api/mails_so/_endpoints   # public; lists every endpoint
Call:     POST https://api.mcp.ai/api/mails_so/<endpoint>
  Authorization: Bearer sk_live_…   # create one at https://mcp.ai/settings/api-keys
  Content-Type: application/json
  Body: { …args }   →   { "ok": true, "tool": "<id>", "result": { … } }

## Developer docs
How to use (MCP or REST), markdown: https://mcp.ai/mails_so/skill.md
Postman collection (v2.1): https://mcp.ai/mails_so/postman.json

## Tools
- mails_so_retrieve_batch_results(id: string) — Tool to retrieve results of a bulk validation job. Use after submitting a batch and you have its ID.
- mails_so_validate_bulk_emails(emails: string[]) — Tool to validate multiple email addresses in bulk. Use when you need to confirm deliverability of a list of emails at once.
- mails_so_validate_single_email(email: string) — Tool to validate a single email address. Use when you need to check deliverability and quality details before sending an email.

## Example prompts
- "What can I do in Mails.so?"
- "Show me a summary of my Mails.so account"

## Links
Docs: https://mcp.ai/docs/mcps/mails_so
Website: https://mcp.ai/mcps/mails_so