Resend

Resend is a transactional email API built for developers. It handles the unglamorous parts of sending email that actually reach an inbox — domain authentication, deliverability, bounce and complaint handling — behind a clean API, and lets you write templates as React components rather than hand-maintained HTML tables.

We use it for transactional mail: sign-ins, notifications, receipts. React Email is the part that removes real pain. Email HTML is a genuinely hostile format, and being able to build a template with components and preview it locally turns a dreaded task into an ordinary one.

SendGrid and Mailgun are the incumbents — more features, more configuration, and an interface that shows its age. Postmark is the one to compare on deliverability, where it has a long reputation for transactional mail specifically. Amazon SES is dramatically cheaper at volume and gives you almost nothing else, which makes it a good destination once your sending is large and predictable rather than a good starting point. For most teams the deciding factor is how fast you can go from nothing to a sent email, and that is where Resend is strongest.