What it does
Mailgun Inspect checks how an email looks across clients and devices before you send it through your existing provider. It succeeds Email on Acid and offers layout previews plus package-specific link, image, accessibility, code and spam checks. New accounts can try Inspect for 30 days.
Count a preview as one client or device screenshot, not one email design. Testing a message across 50 clients consumes 50 previews in Mailgun Inspect. Basic includes 1,000 previews a month and Premium 2,000, with excess previews charged separately. The other included QA checks are unlimited.
Inspect works with any email service provider and cannot send the campaign itself. Its Chrome extension can test a message while you are editing it: connect your Mailgun account with an account-level API key, select the clients and checks, then choose Run Preview. Match the extension's US or EU region to your account. You can rerun just the previews affected by a correction. Keep the tested HTML and the actual sending-platform version aligned when correcting an issue found in a preview. Premium adds checks such as accessibility, code, links and images beyond the Basic preview package.
Email on Acid subscription customers began moving to Inspect in June 2026, with annual accounts transitioning at term end. Existing previews and tests do not transfer in that migration, so a team moving an established QA workflow needs to preserve whatever historical material it still requires before the transition.
Strengths
- The QA workflow can be used independently of the chosen sending provider
- Preview capacity is separated from the other included quality checks
Watch out for
- Each client or device screenshot consumes a preview allowance
- Existing Email on Acid previews and tests are not transferred during migration
Best for
- Email teams checking rendered campaigns across clients before delivery through an existing sender
Sources
- Mailgun Inspect email quality assurance (Oct 27, 2026)
- Mailgun Inspect pricing and migration FAQ (Oct 27, 2026)
- Getting Started with the Mailgun Inspect Chrome Extension (Oct 27, 2026)