"An open-source relational database management system" matching MCP connectors:

Give an agent its own inbox: send, receive, and pull signup codes from real email.

Test-inbox API for email and SMS: create inboxes, long-poll messages, extract OTPs and links. 34 tools; bearer auth with an mfx_ API key (free tier).

Open-source MCP server that gives AI agents access to real email and calendar in one npm install. Solves the problem of AI agents hitting a wall when they need your inbox.

Shared inbox and customer support platform for teams. Manage email conversations, assignments, labels, internal notes, contacts, and replies. 29 tools. Connect with your Helpmonks access token.

Give an AI agent its own inbox — receive email as a webhook, send over a verified domain.

InboxPolicy is an MCP email-verification server for agents. Get an actionable verdict: send, send_with_caution, review, retry_later, or avoid, with confidence and SMTP evidence, plus tools for detailed verification, asynchronous batches, and usage tracking

Email A/B tests for AI agents: subject lines, managed sends, open/click tracking, and results.

First-party MCP server for Fastmail, including email, contacts, and calendars. See: https://www.fastmail.com/blog/an-mcp-server-for-fastmail/

Run personalised outreach campaigns and manage conversations using a virtual computer equipped with email capabilities, research tools, and workflow automation. Email Outreach by OpenHelm enables your agent to carry out work such as: • Prospect research • Personalised outbound email campaigns • Lead qualification • Follow-up sequences • Inbox monitoring and response handling

Cold email, email warmup, LinkedIn outreach, and B2B lead database via MCP.