Mailgun

Mailgun is an email API built for developers who need reliable delivery without platform overhead. The free tier allows 100 emails per day indefinitely, making it practical for small projects and testing. You get direct SMTP and API access, webhook event tracking, and detailed bounce and complaint analytics to monitor your email health.

Mailgun fits developers and technical teams shipping applications that send transactional mail (password resets, confirmations) or light marketing campaigns. It's not a drag-and-drop editor or campaign builder; if you're comfortable writing code to send email, Mailgun's simplicity and transparency on delivery rates make it a strong choice over heavier platforms.