Spam testing helps you catch content issues that could cause your email to be filtered to spam before it reaches the inbox.
In Inspect, spam testing runs automatically with every preview - no extra setup required.
Note: Spam testing is not available for users on Basic subscriptions.
How It Works
When you run a preview, Inspect automatically:
- Sends your email HTML from Mailgun-controlled IPs to a mini seed list of major email providers and spam filters.
- Reports back whether you are expected to pass or fail at each filter.
Important notes:
- Find this information on the Spam check tab inside your test.
- This is a content-only check. It does not evaluate your sending reputation, domain, or IP health.
- Results can take up to 10 minutes to process.
Understanding Results
- Pass - Likely to reach the inbox.
- Fail - May be filtered as spam.
Results are grouped by provider (e.g., B2B, B2C) to help you quickly spot issues.
What to Do Next
- Focus on any Fail results - each provider has different reasons it may filter content to spam.
- Re-test after making changes.
- Use results as guidance, not a guarantee of inbox placement.
What This Doesn't Cover
Spam testing does not evaluate:
- Sending reputation (IP or domain)
- Authentication (SPF, DKIM, DMARC)
Use Mailgun Optimize if you need a full deliverability analysis.
Reality Check
A "pass" doesn't guarantee inbox placement - and a "fail" doesn't mean your email won't be delivered.
Use spam testing to catch obvious content issues before sending.