KaiMail

Free SMTP relay on the msgwing.com domain, up to 200 emails/day, no paid tier. Sends from a shared @msgwing.com address only (no custom domain). Ready-to-run code examples in 15 languages plus Windows Server/Linux/network printer setup guides. ⬆️ Back to Top

email automation workflows, 5k tracked events and unlimited contacts free.

Open source, self-hostable email alias/forwarding solution. Free 10 Aliases, unlimited bandwidth, unlimited reply/send. Free for educational staff (student, researcher, etc.).

Transactional emails API for developers. 3,000 emails/month, 100 emails/day free, one custom domain.

Free API for temporary email testing, free public email hosting, outbound capture, email-to-slack/websocket/webhook (1,500 monthly API limit)

Prevent users to sign up with temporary email addresses, 120 requests/hour (86,400 per month)

SMTP relay and email API for developers. 5,000 emails per month, unlimited domains, free email verification, blacklist monitoring, mail tester and more.

Ethereal is a fake SMTP service, mainly aimed at Nodemailer and EmailEngine users (but not limited to). It's an entirely free anti-transactional email service where messages never get delivered.