Resend

Modern email sending API. TypeScript SDK, React Email templates, custom domain. The Stripe of emails.

Strengths

Native TypeScript SDK, send an email in 5 lines of typed code
React Email: email templates in JSX/TSX, end of hand-written HTML templates
Complete logs dashboard, see every sent email, status, errors
Easy custom domain, DKIM/DMARC configured automatically
One sending subdomain per use: one for what the app sends (sign-up, invoice, forgotten password), one for marketing. Each subdomain carries its own reputation, and Resend recommends it in its documentation: badly received marketing does not contaminate the emails the app must deliver. Verify each subdomain, copy the SPF and DKIM records shown, add a DMARC record ([Shirin Jam](https://www.instagram.com/reel/DfDh7cOgtbV/), [Resend docs](https://resend.com/docs/dashboard/domains/introduction)).

Free tier limited to 100 emails/day, insufficient for volume transactional
Marketing sends exist (Broadcasts, to your contacts), but the law weighs more than the tool: in France, a promotional email to an individual requires prior consent, an unticked box, and every message must offer a simple way to unsubscribe ([CNIL](https://www.cnil.fr/fr/la-prospection-commerciale-par-courrier-electronique)). Between businesses, legitimate interest is enough if the message concerns their work, unsubscribing stays mandatory. It is the only one of the "nine ways to get fined with your SaaS" still readable in [the video by paulemile.ia](https://www.instagram.com/reel/Dd8XCx_s-QZ/), and the most common.
Young player (2023), less battle-tested than SendGrid or Postmark