Resend

Resend

Developer-focused transactional email API with a clean dashboard and React Email integration. 3,000 emails/month free.

Easy~5 minAPI

Step-by-step

Sign up + add your domain

resend.com → sign up. In the dashboard go to Domains → Add Domain. Resend gives you DKIM + SPF records to add at your DNS provider.

Click Verify DNS Records when added. Wait 5-15 min for propagation.

Generate an API key

Resend → API Keys → Create API Key.

• Name: SendGrail
• Permission: Sending access (most restricted scope, all that's needed)

Click Create. Resend shows the key (starts with re_) — copy it once.

Add the connection in SendGrail

SendGrail → Connections → Add Connection → pick Resend.

Fill in:

• Connection Name: Resend
• From Email: an address on your verified domain
• From Name: display name
• API Key: paste the re_... key from step 2

Click Save.

Test

SendGrail → Test Email → pick Resend → send.

Troubleshooting

• 401 Invalid API key — key is wrong, was revoked, or you copied the visible portion (only first/last chars shown after creation). Re-generate.
• 403 Domain not found or not verified — verify the domain at Resend → Domains. DNS propagation can take up to an hour.
• Free tier limit — 3,000 emails/month, 100/day. Upgrade or use a different connection for high-volume.

What's next

• Email Routing — route specific emails through Resend.
• Failure Alerts — get pinged on rejections.