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Connect Mailgun to RadarSend

Mailgun is an email API that handles the actual delivery of your messages. This guide walks you through connecting your Mailgun account to RadarSend so you can send from your own verified domain.

Before you begin#

  • A Mailgun account (sign up at https://www.mailgun.com); a sending domain added and verified in Mailgun; access to your domain’s DNS; and a RadarSend account with admin access.
  • Note: Mailgun runs two separate regions, US and EU, each on a different API host. Check which region your Mailgun account and domain live in (shown in the Mailgun dashboard) — you’ll select it when you connect in Step 2.

Step 1 — Get your Mailgun credentials#

  • Sign in to Mailgun at https://app.mailgun.com.
  • Add and verify your sending domain. In the left-hand navigation, open Send→Sending→Domains, then click Add New Domain. A subdomain such as mg.yourdomain.com is recommended. Mailgun will list the DNS records to add — the SPF and DKIM (TXT) records are required, plus the tracking (CNAME) record for click and open tracking. Add these records at your DNS provider, then wait for Mailgun to verify the domain (DNS changes can take a few hours, occasionally up to 24–48 hours). You can click Verify DNS settings on the domain to check progress.
  • Get your API key. In the top-right corner, click your profile menu and choose API Security. Click Add new key, give it a description, choose the Developer role, and create it. Copy the key immediately (Mailgun won’t show it again).
    • RadarSend needs a key that can send, read your domain, and manage its webhooks. Developer is the narrowest role that covers all three; Admin also works but grants more than RadarSend uses.
    • A domain Sending API key (under Send→Sending→Domain settings→Sending API keys) won’t work here: it can only send, so the connection test and webhook setup both fail with it.
  • Copy the API key and note your domain name (e.g. mg.yourdomain.com) — you’ll need both in the next step.

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 Mailgun, then click Continue.
  3. On Enter your Mailgun keys, fill in your API Key, your Sending Domain (e.g. mg.yourdomain.com), and choose the Region that matches your Mailgun account (US or EU). Then click Connect & verify.

RadarSend saves the service and runs a live connection test: it looks up your sending domain in Mailgun. When it works, it shows Connected · {your sending domain}.

Step 3 — Delivery, bounce & complaint tracking#

RadarSend sets this up for you as part of Connect & verify. Once the connection test passes, the wizard shows Setting up event webhooks…, then Event webhooks configured. It adds your RadarSend account’s address to the webhooks on your sending domain for Delivered, Permanent Failure, Temporary Failure, Complained, and Rejected. Addresses already there for other tools stay.

To check it later, open the service at Settings → Sending → Sending services → your service. The Webhook delivery section shows Configured with the Bounce, Spam Complaint, and Delivery triggers. Click Re-check to run the check again. Configure webhooks (or Re-configure webhooks) only appears when something needs fixing; fix the cause, then click it to retry.

Tip: Mailgun signs its webhooks. RadarSend verifies those signatures automatically using your API key, so there’s nothing extra to configure.

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 Mailgun domain), then click Continue. Add a Display name and Reply-to, pick your email types, and 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 Mailgun rejects the test, RadarSend shows Mailgun didn’t accept this address with Mailgun’s reason and, when your key can read it, what Mailgun currently says about the domain (for example Pending) or that the domain isn’t on the account yet. Verify the domain in Mailgun using the Open Domains in Mailgun link, then retry. RadarSend doesn’t add domains to your Mailgun account; that’s always done in Mailgun.

Tip: open the service to see the Verified sending domains section, which lists the domains on your Mailgun account and their status. It loads when you open the page; Re-check refreshes it. The Developer key from Step 1 can read it.

Common issues#

  • Domain still unverified / DNS not propagated. Mailgun can’t send until the domain shows as verified. Double-check the SPF, DKIM, and tracking records at your DNS provider and give them time to propagate (up to 24–48 hours).
  • Wrong region. If the Region you picked doesn’t match your Mailgun account, sends fail with “Domain not found” or 404-style errors. Open the service and switch Region between US and EU to match Mailgun.
  • From-address not on the Mailgun domain. Your sending address must be on the domain you verified in Mailgun (e.g. you@mg.yourdomain.com), not a generic Gmail or Outlook address.
  • “Invalid API key” when you connect. Usually a domain Sending API key, which can’t read the domain. Create an account key with the Developer role (Step 1) and update it under API credentials.
  • Webhook not configured. If Webhook delivery doesn’t show Configured, the key’s role likely can’t manage webhooks (an Analyst or Support key can read but not change them). Use a Developer key, then click Configure webhooks.
  • New account limits. New Mailgun accounts are often restricted until you add a payment method — do that in Mailgun if your sends are being blocked or capped.

Good to know#

  • Use a dedicated subdomain (e.g. mg.yourdomain.com) for sending. This keeps your root domain’s reputation separate and protected.
  • Mailgun roles can’t be changed after a key is created. To move a key to Developer, create a new key and revoke the old one.
  • Mailgun lets each webhook event send to up to 3 addresses. RadarSend adds itself beside any other tool’s address. If an event already has 3, webhook setup names it; remove one in Mailgun (Send→Sending→Webhooks), then click Configure webhooks.