About Email on Acid (Mailgun Inspect)
Overview
Email on Acid is an email pre-deployment QA suite that marketers and email developers use to test campaigns before sending. The company has evolved the product into Mailgun Inspect, a next-generation email quality assurance suite built on the Mailgun platform.
Mailgun Inspect delivers pre-send email testing across 100+ email clients and devices, accessibility checks aligned with WCAG 2.2, link and image validation, HTML code analysis, and content spam analysis across major ISPs. The tool is sender agnostic, so it works with any email service provider.
Key Benefits
- Test email rendering across 100+ of the latest email clients and devices before every send.
- Catch accessibility issues against WCAG 2.2 guidelines and prepare for European Accessibility Act (EAA) requirements.
- Validate links and images so every customer touchpoint is optimized.
- Run content spam analysis across major ISPs with B2B and B2C delineation to protect inbox placement.
- Get preview results in under 10 seconds with 99.9% platform uptime.
- Use the suite with any email service provider, since Mailgun Inspect is sender agnostic.
How It Works
Users send their email HTML to Mailgun Inspect, which renders previews across 100+ clients and devices and returns results in under 10 seconds. They then run accessibility, link, image, and spam content checks and fix any flagged issues before sending. Each device screenshot counts as one preview, while link validation, accessibility tests, and spam testing are unlimited.
Use Cases
- Email marketers test campaign rendering across devices and inbox providers before each send.
- Email developers validate HTML code and accessibility ahead of every launch.
- Agencies check client campaign links and images before campaigns go live.
- E-commerce teams confirm promotional emails reach the inbox instead of the spam folder.
- QA teams automate preview testing through the Mailgun Inspect API.
Why Choose This Product
Mailgun Inspect is built on the Mailgun platform, so teams can manage pre-send checks, high-volume delivery, and post-send analysis in one place. The platform holds SOC 2 Type 1, ISO 27001, ISO 27701, and GDPR compliance. Email on Acid customers will migrate to Mailgun Inspect starting in June 2026, and teams pair the tool with their own email service provider because it does not send email itself.
Email on Acid (Mailgun Inspect) Pros & Cons
- Tests email across 100+ of the latest clients and devices
- Accessibility checks aligned with WCAG 2.2 and the EAA
- Content spam analysis across major ISPs with B2B/B2C delineation
- SOC 2 Type 1, ISO 27001/27701, and GDPR compliant
- Sender agnostic, works with any email service provider
- Cannot send email; requires a separate email service provider
- Existing Email on Acid previews and tests are not transferred on migration
- Email on Acid customers must migrate to Mailgun Inspect starting June 2026
Key Features
Email Previews
All plansRender email HTML across 100+ email clients and devices, with each device screenshot counting as one preview.
Link Validation
Premium+Check links in every email so each customer touchpoint is optimized before sending.
Image Validation
Premium+Verify that images render correctly across email clients and devices.
Accessibility Checks
Premium+Test email content against WCAG 2.2 accessibility guidelines, in line with the European Accessibility Act (EAA).
HTML Code Analysis
Premium+Analyze email HTML code for issues that could break rendering across clients.
Spam Content Analysis
Premium+Test content against spam filters across all major ISPs with B2B and B2C delineation.
API Access
All plansAutomate email preview testing through the Mailgun Inspect API.
Email on Acid (Mailgun Inspect) Pricing
View full pricing →- Unlimited users
- 1,000 email previews per month
- 100+ email preview clients & devices
- API access
- Overages $0.15 per preview
- Unlimited users
- 2,000 previews per month
- 100+ email preview clients & devices
- API access
- Accessibility tests, HTML code analysis, link and image validation, spam content checks
- Overages $0.15 per preview
- Unlimited users
- Custom previews allotment
- 100+ email preview clients & devices
- API access
- Accessibility tests, HTML code analysis, link and image validation, spam content checks
| Feature | Basic $99/mo | Premium $199/mo | Contract Custom |
|---|---|---|---|
| Email Previews | |||
| Link Validation | |||
| Image Validation | |||
| Accessibility Checks | |||
| HTML Code Analysis | |||
| Spam Content Analysis | |||
| API Access |
Pricing extracted from the product website and may change. Check the source for current details.
Frequently asked questions about Email on Acid (Mailgun Inspect)
Is Mailgun Inspect the same as Email on Acid?
Yes. Mailgun Inspect is the next generation of Email on Acid's email quality assurance tools, incorporating the QA capabilities users trust and integrating them into the Mailgun platform. It gives senders a single platform to manage the email lifecycle, from pre-send testing to delivery, deliverability, and post-send analysis.
Do I need to migrate from Email on Acid to Mailgun Inspect?
Yes. Beginning in June 2026, current Email on Acid subscription customers will start transitioning to Mailgun Inspect. Customers on annual plans migrate at the end of their current term. Existing previews and tests will not be transferred, and current subscribers receive a special migration discount with details shared later.
What features are included in Mailgun Inspect?
Mailgun Inspect includes email previews, image validation, link validation, accessibility checks, and code analysis. It tests email HTML across 100+ devices and clients, and its accessibility checks follow the latest W3 Web Content Accessibility Guidelines, in line with the European Accessibility Act (EAA).
Is Mailgun Inspect sender agnostic?
Yes. Mailgun Inspect can be used with any email service provider, so you do not need other Mailgun products to use it.
Do I need to be technical or know how to code to use Mailgun Inspect?
No. The platform serves everyone from first-time marketers to seasoned email developers, and you do not need to be technical or know how to code to use it.
Can I send email with Mailgun Inspect?
No. Mailgun Inspect does not send email. To send email via SMTP or API, you need an email service provider such as Mailgun Send.