Knowledge Base Connect a provider Connect Resend to RadarSend

Connect Resend to RadarSend

Resend is an email sending service. This guide walks you through connecting it to RadarSend so you can send email and track delivery, bounces, and complaints.

Before you begin#

  • A Resend account — sign up at https://resend.com if you don’t have one.
  • Access to your domain’s DNS settings (so you can add the records Resend gives you).
  • A RadarSend account with admin access.

Step 1 — Get your Resend credentials#

  1. Sign in to Resend.
  2. Add and verify your sending domain. Go to Domains → Add Domain, enter your domain, and Resend will show you a set of DNS records (DKIM, SPF, and a return-path/MX record). Add each record with your DNS provider, then click Verify DNS Records. Verification can take a few minutes to a few hours while DNS propagates. Your domain shows as Verified once it’s ready.
  3. Create an API key. Go to API Keys → Create API Key, give it a name, and choose the Sending access permission (you can also restrict it to a specific domain). Click to create it, then copy the key — it starts with re_ and is shown only once, so save it somewhere safe.

Step 2 — Add the sending service in RadarSend#

  1. In RadarSend, go to Settings → Sending → Sending services and click + Connect a service.
  2. In the wizard, on Choose your sending service, pick Resend, then click Continue.
  3. On Enter your Resend keys, paste your API Key. Optionally paste a Webhook signing secret (you’ll get this in Step 3). Then click Create.

RadarSend validates the fields and saves the service — it doesn’t live-test Resend, so you’ll confirm sending actually works in Step 4.

Step 3 — Turn on delivery, bounce & complaint tracking#

Set these up manually. Open the service (Settings → Sending → Sending services → your service). The Webhook delivery section shows a webhook URL unique to your account (like https://…/webhooks/resend/…). Copy it.

Then in Resend, go to Webhooks → Add Endpoint, paste the URL, and subscribe to these events:

email.delivered
email.bounced
email.complained

Copy the endpoint’s Signing Secret (it starts with whsec_) and paste it into RadarSend’s Webhook signing secret field — open the service and find it under API credentials — so RadarSend can verify incoming events. Back in RadarSend, click Check to confirm the triggers are on.

Step 4 — Confirm your sending address#

  1. Go to Settings → Sending → Senders and click + Add sender.
  2. Enter your Sending address (it must be on your verified Resend domain) and click Continue. Add a Display name and Reply-to, pick the email types this sender handles, then click Continue.
  3. On Tracking & confirm, choose this service under Sending service (only shown if you have more than one), enter a test recipient, and click Send test.
  4. When the test is accepted, click Save sender.

If the test is rejected because your domain isn’t verified, RadarSend offers Authenticate {domain} (DKIM/SPF) and shows the DNS records to add.

Tip: open the service and click Check verified domains to see which domains Resend has verified.

Common issues#

  • Domain not verified / DNS not propagated. If sending fails, check Domains in Resend — the domain must show Verified. DNS changes can take minutes to hours to propagate; if records don’t validate, re-check them against what Resend shows and click Verify DNS Records again.
  • From-address isn’t on a verified domain. Your sending address must use a domain you’ve verified in Resend. An address on an unverified (or slightly misspelled) domain will be rejected.
  • Free plan / testing restrictions. Until you’ve verified a domain, Resend limits you to sending test emails to your own account’s email address (using its sandbox address). Verify your domain to send to real recipients.
  • Signing secret not entered. If you skip pasting the whsec_ signing secret into RadarSend, signature verification can’t run and delivery/bounce/complaint events may be ignored. Make sure the secret from your Resend webhook endpoint is saved under API credentials.

Good to know#

  • Resend signs its webhooks (using Svix under the hood). Entering the signing secret lets RadarSend cryptographically verify that each event genuinely came from Resend.