Email on Acid is unclaimed —

Email on Acid

The leading email pre-deployment suite·emailonacid.com

Email on Acid is a cloud-based email quality-assurance platform that lets marketers and developers preview and test HTML emails across 100+ email clients and devices before sending. It checks accessibility compliance (WCAG/ADA/EAA), validates links and images, analyzes HTML/CSS code, and screens content for spam triggers across major ISPs. The platform is being succeeded by a next-generation product called Mailgun Inspect, built on the Mailgun platform.

What it's for

Preview emails across 100+ clients and devices before sendingCatch broken layouts and links before sendingTest email accessibility against WCAG 2.2 / ADA / EAA guidelinesCheck HTML and CSS compatibility across email clientsValidate links and images in email contentAnalyze email content for spam-trigger red flagsPreview dark-mode rendering of emails

Features 16

Accessibility checks (WCAG 2.2, ADA, EAA compliance) flagging 45+ issues
Auto-Inbox automatic email processing
Client frame previews
Content spam analysis across major ISPs with B2B/B2C delineation
Customizable user permissions
Dark mode preview optimization
Email previews across 100+ clients and devices
HTML and CSS code analysis
Image validation
Link validation
Postman collection for API testing
RESTful API access
Screenshot authentication with time-rotated, credential-secured URLs
Test storage
Two-factor authentication
Unlimited user seats

At a glance

free trialAPI

TypeWeb app

DeploymentCloud

PlatformsWeb

Formarketers, developers

Integrations

PostmanMailgun Send

Complianceself-reported

SOC 2ISO 27001ISO 27701GDPR

Resources

Docs

Pricing

Prices are displayed in USD by default; a currency selector also offers EUR and GBP display without stated converted amounts. Plans are shown under the 'Mailgun Inspect' branding on the Email on Acid pricing page as the product transitions to that name. Existing annual-plan customers migrate to Mailgun Inspect at the end of their current term (starting June 2026); existing previews and tests will not be transferred.

Basic (Mailgun Inspect)$99/mo

Overage rate: $0.15 per additional preview.

1,000 email previews per month

Premium (Mailgun Inspect)$199/mo

Marked as most popular plan. Overage rate: $0.15 per additional preview.

2,000 previews per month

Contract (Mailgun Inspect)Quote

Custom pricing, contact sales.

Custom preview allotment

Current Email on Acid subscribers will receive a special migration discount for Mailgun Inspect (details to be announced).