Email on Acid is now Mailgun Inspect: what changes for you
Email on Acid customers are moving to Mailgun Inspect. What's different, what it costs, what doesn't come across, and how to decide whether to stay.
· 2 min read
If you use Email on Acid, you've probably had the email: Email on Acid is being replaced by Mailgun Inspect. Here's what that means in practice, based on Mailgun's own announcements and help pages. One thing up front: we make EmailTestr, an alternative, so we've stuck to what Mailgun says publicly and linked to it.
What's happening
Mailgun describes Inspect as a rebuild of Email on Acid on the Mailgun platform, not a rename. Customers are moving in stages:
- Contract customers moved first.
- Subscription customers started moving in June 2026.
- Annual customers move when their current term ends.
Mailgun says existing Email on Acid subscribers get a migration discount.
What it costs
Mailgun Inspect's public plans:
- Basic: $99 a month for 1,000 previews, with the first month free.
- Premium: $199 a month for 2,000 previews, adding accessibility tests, HTML code analysis, link and image validation, and spam content checks.
- Over your limit: $0.15 per extra preview.
- Contract plans: custom pricing through sales.
A preview is one email client or device, so testing one email across 100 clients uses 100 previews. Users are unlimited on every plan.
What's different
- Checks are on the higher plan. Link and image validation, accessibility and code analysis are part of Premium, not Basic.
- Some features weren't ready at launch. Mailgun's API migration notes said spam testing wasn't supported yet and there was no code editor, with the editor due to follow.
- Your history doesn't come with you. Past Email on Acid tests and previews don't move to Inspect.
- There's a Chrome extension for running tests from your browser.
Should you stay?
Stay with Inspect if you need a very wide range of clients and devices, including older Outlook versions, or you already send with Mailgun and want everything in one place.
Look around if you mostly check the same few clients, and $99 to $199 a month is more than that job needs. Our Email on Acid alternatives guide compares the options and prices, and there's a side-by-side page for EmailTestr and Mailgun Inspect.
Facts checked in November 2026 from Mailgun's public pages. Plans change, so check Mailgun's site before you decide.
Sources: Mailgun: Inspect, the next generation of Email on Acid, Mailgun Inspect pricing, Mailgun: migrate from Email on Acid to Inspect, Mailgun: API migration plan, Mailgun: understanding usage in Inspect.