Tools / Postmark / Postmark vs Resend
Transactional email that lands in the inbox, fast.
Postmark is a transactional email delivery service that sends application email — password resets, receipts, notifications — through a REST API or SMTP. The site says it has been delivering email since 2010 and has sent billions of messages for companies of all sizes. Sending works through an API with official libraries for Node.js, Python, Ruby on Rails, Ruby, PHP, and C#, plus a plain curl example for testing. API requests include a MessageStream field (the sample uses "outbound"), which separates types of outbound email. Developer documentation lives at postmarkapp.com/developer, and you can sign up for a free trial from the homepage. The homepage names IKEA, 1Password, Asana, Webflow, Minecraft, UNICEF, Paddle, Indie Hackers, Litmus, and Moz among its customers. Several customer quotes on the page describe migrating to Postmark from SendGrid or Mailgun, citing deliverability and speed of delivery.
The email API developers actually like.
Resend is an email platform built for developers. It sends transactional and marketing email through an API with SDKs for Node.js, Python, Ruby, PHP, Go, Rust, Java, Elixir, .NET, and more, plus REST and SMTP interfaces. Emails can be sent from code, composed in a visual editor, or built as React components using react-email, Resend's open source component library.