# Email on Acid vs Mailpit

**Leader by Vioscale score:** Email on Acid

| Attribute | Email on Acid | Mailpit |
|---|---|---|
| **Vioscale score** | 58.3 (66% (medium)) | 39.6 (23% (low)) |
| activity.commits_last_30d | - | 36 |
| adoption.dependent_repos | - | 0 |
| adoption.github_stars | - | 10,208 |
| deployment.options | `{"cloud":true}` | `{"self_hosted":true}` |
| description.long | 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. | A minimal email testing tool that intercepts SMTP traffic and provides a web UI plus REST API for validating and testing email functionality during development. |
| features.capabilities | `{"open_source":false,"sms_testing":false,"api_assertions":true,"spam_score_check":true,"ci_cd_integration":false,"rendering_preview":true,"multi_user_inboxes":false,"production_sending_addon":false,"blocklist_deliverability_check":true}` | - |
| integrations.count | - | 1 |
| integrations.list | - | `[{"name":"SpamAssassin"}]` |
| language.primary | - | Go |
| license.spdx | - | MIT |
| market.availability | `{"primaryMarkets":["US"],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` | - |
| platform.support | `{"web":true}` | `{"web":true}` |
| pricing | `{"type":"subscription","plans":[{"free":false,"name":"Basic","summary":"$99/month, $0.15 per preview overage","features":["1,000 email previews per month","100+ email preview clients and devices","Unlimited users","API access","Overage charges for additional previews"],"commitment":"monthly","components":[{"kind":"fixed","amount":99,"period":"month","currency":"USD"},{"per":{"qty":1,"unit":"preview"},"kind":"metered","amount":0.15,"currency":"USD"}],"description":"Email preview testing with API access","contactSales":false,"includedLimits":{"previews":"1,000/mo","clients_devices":"100+"}},{"free":false,"name":"Premium","summary":"$199/month","features":["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","Link and image validation","Spam content checks across major ISPs"],"commitment":"monthly","components":[{"kind":"fixed","amount":199,"period":"month","currency":"USD"}],"description":"Full QA suite with accessibility testing and content analysis","contactSales":false,"includedLimits":{"previews":"2,000/mo","clients_devices":"100+"}},{"free":false,"name":"Custom","summary":"Custom pricing","features":["Custom preview allotments","Phone and chat support","Dedicated support documentation"],"description":"Custom preview allotments and enterprise support","contactSales":true}],"summary":"From $99/month. 7-day free trial.","currency":"USD","freeTier":false,"sourceUrl":"https://www.emailonacid.com/pricing/","retrievedAt":"2026-08-25T12:11:37.247Z","freeTrialDays":7,"startingPrice":{"amount":99,"period":"month","currency":"USD"},"billingPeriods":["month"]}` | - |
| pricing.free_tier | no | - |
| pricing.model | commercial | - |
| pricing.price_level | high | - |
| pricing.starting_price | `{"amount":99,"currency":"USD"}` | - |
| pricing.transparent | yes | - |
| release.cadence_days | - | 11 |
| release.history | - | `[{"url":"https://github.com/axllent/mailpit/releases/tag/v1.31.0","date":"2026-08-22T00:00:16Z","type":"stable","version":"v1.31.0"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.7","date":"2026-08-08T09:51:14Z","type":"stable","version":"v1.30.7"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.6","date":"2026-07-28T04:08:26Z","type":"stable","version":"v1.30.6"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.5","date":"2026-07-20T04:18:08Z","type":"stable","version":"v1.30.5"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.4","date":"2026-07-09T03:37:30Z","type":"stable","version":"v1.30.4"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.3","date":"2026-06-27T09:32:36Z","type":"stable","version":"v1.30.3"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.2","date":"2026-06-17T03:38:53Z","type":"stable","version":"v1.30.2"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.1","date":"2026-05-28T10:02:23Z","type":"stable","version":"v1.30.1"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.0","date":"2026-05-14T05:00:22Z","type":"stable","version":"v1.30.0"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.7","date":"2026-04-16T06:01:06Z","type":"stable","version":"v1.29.7"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.6","date":"2026-04-05T10:03:15Z","type":"stable","version":"v1.29.6"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.5","date":"2026-03-29T04:48:58Z","type":"stable","version":"v1.29.5"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.4","date":"2026-03-22T04:57:48Z","type":"stable","version":"v1.29.4"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.3","date":"2026-03-10T02:32:01Z","type":"stable","version":"v1.29.3"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.2","date":"2026-02-24T23:31:43Z","type":"stable","version":"v1.29.2"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.1","date":"2026-02-13T08:02:33Z","type":"stable","version":"v1.29.1"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.29.0","date":"2026-02-01T03:13:50Z","type":"stable","version":"v1.29.0"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.28.4","date":"2026-01-24T21:08:56Z","type":"stable","version":"v1.28.4"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.28.3","date":"2026-01-18T08:38:39Z","type":"stable","version":"v1.28.3"},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.28.2","date":"2026-01-10T03:21:02Z","type":"stable","version":"v1.28.2"}]` |
| reliability.sla_pct | 99.9 | - |
| security.gdpr | yes | - |
| security.iso27001 | yes | - |
| security.soc2 | yes | - |
| security.vulnerabilities | - | `{"count":13,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=go&package_name=github.com%2Faxllent%2Fmailpit&per_page=100","last_12m":13,"max_severity":"HIGH"}` |

## Capabilities (Email Testing Dev)

| Capability | Email on Acid | Mailpit |
|---|:--:|:--:|
| **Capabilities** |  |  |
| API assertions | ✓ | - |
| Rendering preview | ✓ | - |
| Spam score check | ✓ | - |
| Blocklist deliverability check | ✓ | - |
| SMS testing | ✗ | - |
| Production sending addon | ✗ | - |
| Ci cd integration | ✗ | - |
| Multi user inboxes | ✗ | - |
| Open source | ✗ | - |

*Source: Vioscale. Generated 2026-09-01T14:47:19.609Z. "-" = undocumented, not absent.*