Best Alternatives to Agent Email List — Free SMTP Relay for AI Agents

Emailmd

Runtime: npx

Render, lint, and preview markdown emails through MCP using hosted HTTP or local stdio transport.

Line Bot MCP Server

Runtime: npx

Verified

Connects an AI agent to LINE Messaging API for messaging, user profiles, quotas, followers, and rich-menu management.

Telnyx

Runtime not confirmed

Official TypeScript library for the Telnyx API

Google Workspace

Runtime: npx

Give AI agents access to Gmail, Calendar, Drive, and more — multi-account, manifest-driven

Atomic Mail

Runtime: npx

Programmable email inbox for AI agents — JMAP, PoW auth, stdio MCP server.

Engagelab Email

Runtime: npx

Send, receive, monitor and reply to email from AI agents with threaded inbox context.

E2a — email for AI agents

Runtime: uvx

Authenticated email gateway for AI agents — per-agent inboxes, HITL approval, SPF/DKIM verified.

Threadline MCP

Runtime: npx

Agent-to-agent messaging relay. Discover agents, send messages, and receive replies. Zero-config.

Mailbuttons

Runtime: npx

Governed email for AI agents: sandbox inboxes, server-side policy gate, tamper-evident audit.

Lumail

Runtime: npx

Official Lumail email marketing MCP for campaigns, subscribers, and workflows.

Telegram MCP

Runtime: npx

Connects AI assistants to Telegram for account data, dialogs, messages, read status, and draft replies.

Telegram MCP

Runtime: uvx

Connects MCP-compatible clients to Telegram for account, chat, message, contact, media, and administrative operations.