Resend is the developer-first transactional email API: a small clean REST API, a React SDK, email components, and sensible defaults. It is the right choice for a new product that sends transactional mail. It stops being the right choice when you need marketing campaigns, SMTP at scale, a longer provider track record, or the cheapest possible cost per email at high volume. Here is what the alternatives are and how to move.
SendGrid is the alternative if you need marketing campaigns or a bigger ecosystem: campaigns, templates, segmentation, a free tier, and a decade-plus of history. The trade-off is a shared IP pool and more configuration surface.
Postmark is the alternative if deliverability is the whole job: transactional only, a strict reputation policy on its IPs, streams to isolate mail types. It costs more per email and does not do marketing.
Mailgun is the alternative if you want a cheaper, more flexible pipe at volume: API and SMTP, shared or dedicated IPs, and competitive pricing at the high end.
Amazon SES is the alternative if cost at scale is the whole decision: cheapest per email, rawest tooling, and you own more of the reputation work.
Resend is a younger provider, and its shared-IP model means your reputation is partly shared until you move to dedicated IPs. If you are hitting deliverability problems on Resend, the first move is to audit your own domain, not to switch providers. A broken SPF include or a missing DKIM selector will follow you anywhere.
1. Add the new provider to your domain first. Its SPF include and DKIM selectors go alongside Resend's.
2. Verify and ramp. Confirm the new provider sends correctly, then ramp volume. A dedicated IP needs a warmup; a shared pool needs sane volume from day one.
3. Cut over the sending. Point your application at the new API and keep Resend's records for a rollback window.
4. Remove Resend from SPF. After the cutover is stable, drop the Resend include so your SPF only authorizes providers you actually use.
5. Watch bounces and DMARC reports for two weeks. A spike is a configuration problem on your side.
Whichever provider you pick, the setup on your domain decides the outcome.
Run a free audit of your sending domain. It checks SPF, DKIM, DMARC, MX, TLS and IP reputation in about 30 seconds, no account needed.
Check my domain free