Mailgun API Key Tester

Test any AI or API key in your browser — instantly see if it's valid, and why it isn't. Nothing is stored.

Test your Mailgun API key with the messages endpoint

Data verified 2026-07-13

Key format & how to get one

1. Visit https://app.mailgun.com/ and sign up/login 2. Go to Settings > API Keys 3. Copy your Private API Key 4. Note your domain (e.g., sandbox-xxx.mailgun.org) 5. Free tier: 5,000 emails/month for 3 months

Mailgun API docs →

Cannot test this key from your browser

This provider blocks in-browser requests or requires a server-side secret. Test it from a terminal instead:

curl -sS -X POST https://api.mailgun.net/v3/sandbox-xxx.mailgun.org/messages -u api:{{KEY}} -F from='test@example.com' -F to='test@example.com' -F subject='Test Email' -F text='Hello world!'

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