Email on Acid vs Testmail.app
On the evidence we track, Testmail.app leads this comparison with a composite score of 70/100. Scores are only directly comparable because these tools share a category; the full breakdown and every source is below.
Capabilities
Feature-by-feature on the axes that matter for email testing dev. “-” means undocumented, not absent.
What each one is
The product in its own terms, so the numbers below have context.
Email on Acid
Tests email campaigns across 100+ email clients and devices to identify rendering issues, validate content for inbox compatibility, check accessibility compliance, and detect deliverability problems before sending.
Testmail.app
LeaderA programmable email testing service that provides temporary email addresses and mailboxes for automated testing, allowing developers to validate email delivery and functionality without affecting real customers.
Pricing
List pricing as published by each vendor, with the date we read it. Always verify at the source before you buy.
Email on Acid
From $99/month. 7-day free trial.
- Basic$99/month, $0.15 per preview overage
- 1,000 email previews per month
- 100+ email preview clients and devices
- Unlimited users
- API access
- Overage charges for additional previews
- Premium$199/month
- 2,000 email previews per month
- 100+ email preview clients and devices
- Unlimited users
- Accessibility tests (WCAG 2.2 / European Accessibility Act compliance)
- HTML code analysis
- +2 more
- CustomContact sales
- Custom preview allotments
- Phone and chat support
- Dedicated support documentation
Testmail.app
LeaderFree forever (100 emails/month) plus 14-day free trial. Paid plans from $9–$269/month.
- FreeFree
- 100 emails/month
- Unlimited users, email addresses, and mailboxes
- 1 day retention
- Essential$9/month (annual) or $12/month (monthly)
- 10,000 emails/month
- 1-3 days retention
- One random namespace
- Full API access
- Pro$29/month (annual) or $39/month (monthly)
- 50,000 emails/month
- Unlimited custom namespaces
- Visual viewer
- Priority support
- Enterprise$89/month (annual) or $129/month (monthly)
- 1,000,000 emails/month
- Custom retention
- SSO with SAML 2.0 or OIDC
- Enterprise invoicing
- 99.99% uptime SLA
- Plus$269/month (annual) or $299/month (monthly)
- 10,000,000 emails/month
- All Enterprise features
- Unlimited custom domains
- Custom contracts with enterprise compliance support
- SCIM support
Platform & deployment
Where each product runs and how it can be hosted. A dash means undocumented, not unsupported.
Integrations
What each product connects to. Counts come from the vendor's own integration directory where one exists.
Email on Acid
Not documented yet.
Testmail.app
Leader- Microsoft Entra ID
- Okta
- OneLogin
Email on Acid or Testmail.app: which one depends on you
A composite score cannot know your constraints. Describe them and both get re-weighted against what you actually need, with the evidence behind every position.
Free to run, no account needed to start. How the evaluation works
Comparison generated from independently-sourced facts. Every value links to its source and retrieval date. See the method.