# Email on Acid vs GreenMail

| Attribute | Email on Acid | GreenMail |
|---|---|---|
| **vioscaleAI score** | 57.7 (64% (medium)) | 55.9 (31% (low)) |
| activity.commits_last_30d | - | 30 |
| adoption.dependent_repos | - | 2,587 |
| adoption.github_stars | - | 747 |
| content.faq | `[{"answer":"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. It is indexed under Email Testing Dev.","source":"https://www.emailonacid.com/pricing/","question":"What is Email on Acid?","confidence":0.6},{"answer":"Email on Acid is a paid product; published pricing starts at $0.15. It is sold across 3 plans (Basic, Premium and Custom). There is no free tier. Prices are published openly on the vendor's own pricing page. Pricing changes often, so verify at source before relying on it.","source":"https://www.emailonacid.com/pricing/","question":"How much does Email on Acid cost?","confidence":0.6},{"answer":"We have confirmed browser-based access to Email on Acid. That is the extent of what we could verify from public sources, so it may well offer desktop or mobile clients we have not indexed.","source":"https://www.emailonacid.com/pricing/","question":"What platforms does Email on Acid support?","confidence":0.6},{"answer":"We have only confirmed a cloud / SaaS deployment for Email on Acid, so it appears to be vendor-hosted. If a self-hosted option exists we have not found it documented publicly.","source":"https://www.emailonacid.com/pricing/","question":"Can Email on Acid be self-hosted?","confidence":0.6},{"answer":"We have independently confirmed SOC 2, ISO 27001 and GDPR for Email on Acid. Certifications we do not list are ones we have not been able to verify from public sources, which is not the same as Email on Acid not holding them. Always confirm compliance directly before you rely on it.","source":"https://www.emailonacid.com/blog/article/email-marketing/gdpr-compliance/","question":"What security certifications does Email on Acid have?","confidence":0.7},{"answer":"Email on Acid is available worldwide. Its primary market is the United States.","source":"https://www.emailonacid.com/pricing/","question":"Where is Email on Acid available?","confidence":0.5}]` | `[{"answer":"A testing framework that emulates email server behavior (SMTP, POP3, IMAP) to help developers verify email functionality in their applications during testing, without requiring actual email infrastructure or sending real messages. It is indexed under Email Testing Dev.","source":"https://greenmail-mail-test.github.io/greenmail/","question":"What is GreenMail?","confidence":0.6},{"answer":"GreenMail is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.","source":"https://greenmail-mail-test.github.io/greenmail/","question":"Is GreenMail free to use?","confidence":0.6},{"answer":"Yes. GreenMail can be deployed self-hosted, so it does not have to run on the vendor's infrastructure.","source":"https://greenmail-mail-test.github.io/greenmail/","question":"Can GreenMail be self-hosted?","confidence":0.6},{"answer":"Yes. GreenMail is published under the Apache-2.0 licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.","source":"https://github.com/greenmail-mail-test/greenmail","question":"Is GreenMail open source?","confidence":0.95}]` |
| 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. | GreenMail is a lightweight testing tool that simulates SMTP, POP3, and IMAP email servers for application testing. It allows developers to extract, verify, and modify test messages within a contained environment while supporting SSL encryption. |
| 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}` | `{"open_source":true,"sms_testing":false,"api_assertions":true,"spam_score_check":false,"ci_cd_integration":true,"rendering_preview":false,"multi_user_inboxes":true,"production_sending_addon":false,"blocklist_deliverability_check":false}` |
| language.primary | - | Java |
| license.spdx | - | Apache-2.0 |
| market.availability | `{"primaryMarkets":["US"],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` | - |
| platform.support | `{"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"]}` | `{"type":"open_source","freeTier":true,"sourceUrl":"https://greenmail-mail-test.github.io/greenmail/","retrievedAt":"2026-10-13T22:35:44.503Z"}` |
| pricing.free_tier | no | yes |
| pricing.model | commercial | open_source |
| pricing.price_level | high | free |
| pricing.starting_price | `{"amount":99,"currency":"USD"}` | - |
| pricing.transparent | yes | - |
| release.cadence_days | - | 29 |
| release.history | - | `[{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.14","date":"2026-09-19T13:28:58Z","type":"stable","version":"release-2.1.14"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.13","date":"2026-08-23T10:02:24Z","type":"stable","version":"release-2.1.13"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.12","date":"2026-08-05T18:50:04Z","type":"stable","version":"release-2.1.12"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.11","date":"2026-07-15T19:46:18Z","type":"stable","version":"release-2.1.11"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.10","date":"2026-07-14T09:57:41Z","type":"stable","version":"release-2.1.10"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.9","date":"2026-06-14T17:01:37Z","type":"stable","version":"release-2.1.9"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.8","date":"2025-12-14T17:26:41Z","type":"stable","version":"release-2.1.8"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.7","date":"2025-10-07T21:21:09Z","type":"stable","version":"release-2.1.7"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.6","date":"2025-09-28T18:47:25Z","type":"stable","version":"release-2.1.6"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.5","date":"2025-08-10T18:41:13Z","type":"stable","version":"release-2.1.5"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.4","date":"2025-07-13T16:54:29Z","type":"stable","version":"release-2.1.4"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.3","date":"2025-02-04T20:59:33Z","type":"stable","version":"release-2.1.3"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.2","date":"2024-11-30T11:21:39Z","type":"stable","version":"release-2.1.2"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.1","date":"2024-11-17T21:12:57Z","type":"stable","version":"release-2.1.1"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.0","date":"2024-10-05T16:20:21Z","type":"stable","version":"release-2.1.0"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.0-rc-1","date":"2024-05-31T20:05:52Z","type":"stable","version":"release-2.1.0-rc-1"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.0-alpha-4","date":"2024-01-28T18:47:27Z","type":"stable","version":"release-2.1.0-alpha-4"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-1.6.15","date":"2023-12-03T15:51:55Z","type":"stable","version":"release-1.6.15"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.0.1","date":"2023-11-17T21:42:15Z","type":"stable","version":"release-2.0.1"},{"url":"https://github.com/greenmail-mail-test/greenmail/releases/tag/release-2.1.0-alpha-3","date":"2023-11-04T13:17:06Z","type":"stable","version":"release-2.1.0-alpha-3"}]` |
| reliability.sla_pct | 99.9 | - |
| security.gdpr | yes | - |
| security.iso27001 | yes | - |
| security.scorecard | - | 6.6 |
| security.soc2 | yes | - |
| security.vulnerabilities | - | `{"count":0,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=maven&package_name=com.icegreen%3Agreenmail&per_page=100","last_12m":0,"max_severity":null}` |

## Capabilities (Email Testing Dev)

| Capability | Email on Acid | GreenMail |
|---|:--:|:--:|
| **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: vioscaleAI. Generated 2026-10-16T18:33:40.080Z. "-" = undocumented, not absent.*