Mailgun and Resend are both developer-friendly email APIs, but they came from different eras. Mailgun is a mature, flexible workhorse: API, SMTP, shared or dedicated IPs, marketing features, and pricing that gets cheap at volume. Resend is newer and narrower: a clean transactional API, a React SDK, email components, and a product that stays out of your way.
Mailgun gives you more surface: SMTP and API, custom domains, webhooks, marketing features, and dedicated IPs on higher tiers. It is the better choice when your sending needs are varied or you expect to change them.
Resend gives you less surface on purpose: transactional email from an API, with a small set of well-documented options. It is the better choice when you know exactly what you are sending and want the shortest path from code to inbox.
Mailgun sends from a shared IP pool by default, with dedicated IPs available on higher tiers. Resend sends from shared infrastructure by default and offers dedicated IPs on higher plans. Both mean your reputation is partly shared until you move to dedicated IPs, and both need the same DNS hygiene: SPF, DKIM, DMARC, and a warmup if you ramp volume fast.
Mailgun prices by monthly volume with a free tier and is cheap at high volume. Resend prices by monthly volume with a free tier and is competitive at low and mid volume. If you send a lot, Mailgun has historically been the cheaper pipe. Check current pricing before you commit.
Pick Mailgun if you need flexibility, SMTP, or high-volume cost efficiency. Pick Resend if you want the cleanest developer experience for transactional mail and are happy with a younger provider. On either one, the SPF, DKIM and DMARC records on your domain decide most of the outcome.
Whichever provider you pick, the setup on your domain decides the outcome.
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