How do you migrate from SendGrid to Resend in 2026?

How to Migrate from SendGrid to Resend (May 2026)

Resend, founded in 2023, is a developer-focused transactional email API. SendGrid (acquired by Twilio in 2019, now Twilio SendGrid) is the long-standing incumbent. Migrations are typically driven by Resend's simpler API, React Email integration, and pricing for mid-volume workloads.

Step 1: Verify Sending Domains in Resend

In the Resend dashboard, add each sending domain. Resend will provide DNS records (SPF, DKIM, MX for inbound if needed). Add them to your DNS provider but do not change existing SendGrid SPF/DKIM yet. Both can coexist on the same domain during migration as long as the SPF includes statement is correct.

Step 2: Port Templates

SendGrid templates use Handlebars-style substitutions. Resend recommends React Email — JSX components that render to email-safe HTML.

Two approaches:

• Lift-and-shift: convert each template by copying the HTML and re-templating with React Email's primitives (<Container>, <Text>, <Link>).
• Rewrite: use this as the moment to consolidate templates. Most teams find they have 2-3x more templates than they need.

Step 3: Swap the API Client

In code, replace SendGrid's SDK call with Resend's. The shape is similar:

// Before
await sgMail.send({ to, from, subject, html });

// After
await resend.emails.send({ to, from, subject, html });

Wrap the call in a thin abstraction so you can flip between providers per-call (or by feature flag) during the migration window.

Step 4: Run Dual-Send for a Verification Window

Send a representative slice of email traffic (e.g., 10% of transactional sends) through Resend, with the abstraction routing the remaining 90% through SendGrid. Run this for 5-10 days. Monitor:

• Bounce rate (should be the same or lower).
• Spam complaints (Resend has a webhook for these).
• Opens and clicks if you track them.
• Customer support reports of missing or formatting-broken emails.

Step 5: Cut Over and Decommission

Once dual-send confirms parity, ramp Resend traffic to 100%. Update SPF to remove SendGrid include if no longer needed. Cancel the SendGrid plan after a 30-day buffer to ensure no scheduled jobs still call it.

What Usually Goes Wrong

• Reply-to handling. Resend and SendGrid handle reply-to slightly differently. Verify in dual-send that replies route correctly.
• Suppression lists. Export from SendGrid, import to Resend, or you will resend to addresses that bounced or unsubscribed.
• Webhooks. Update webhook URLs and verify event payloads, which differ in shape between providers.
• Custom unsubscribe pages. SendGrid has built-in unsubscribe groups; Resend expects you to handle unsubscribe state in your application.

Editor's Note: We migrated a 9-person AI startup from SendGrid Pro to Resend Pro over 11 days. Direct cost dropped from ~$240/month to $20/month for their volume, and the developer experience for React Email won the team over before the cost did. The honest caveat: their suppression list had 2,400 addresses we missed on first import, and the first day of full cutover sent to ~40 of them before the engineer noticed and fixed the import. Always export and verify suppression lists before cutover.

Caveats

Migration cost and complexity scale with template count and traffic volume. For very high-volume senders (>500K emails/month), validate Resend's rate limits and dedicated-IP options before committing. Pricing for both vendors changes; verify current numbers before starting the project.