Email sending for AI agents
4 APIs compared on price, free tier, MCP support and real usage. Prices from the vendors' pricing pages, checked Oct 9, 2026.
Free to start
4 of 4
Resend, Twilio SendGrid, Postmark
Official MCP server
3 of 4
plug straight into Claude Code, Cursor and others
| API | Free | Price | SDK downloads / wk | GitHub stars | MCP |
|---|---|---|---|---|---|
| Resend Developer email API for sending and receiving transactional and marketing email. |
3,000 emails/month, 100/day, 3 domains | Free plan · paid from $20/mo | 16.2M | 964 | MCP |
| Twilio SendGrid High-volume email API and SMTP relay with deliverability tooling and marketing campaigns. |
Free trial: 100 emails/day for 60 days | Free plan · paid from $19.95/mo | 9.7M | 3,052 | MCP (community) |
| Postmark Transactional email API and SMTP service focused on fast delivery, with inbound processing. |
100 emails/month (Developer plan, never expires) | Free plan · paid from $15/mo | 1.2M | 361 | MCP |
| AgentMail Email inboxes for AI agents via API - create inboxes, send, receive and reply in threads. |
3 inboxes, 3,000 emails/month (100/day), 3 GB storage | Free plan · paid from $20/mo | 773K | 72 | MCP |
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