# GreenMail vs MailSlurp

| Attribute | GreenMail | MailSlurp |
|---|---|---|
| **vioscaleAI score** | 55.9 (31% (low)) | 52.3 (54% (medium)) |
| activity.commits_last_30d | 30 | - |
| adoption.dependent_repos | 2,587 | - |
| adoption.github_stars | 747 | - |
| content.faq | `[{"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}]` | `[{"answer":"MailSlurp is an email and SMS testing platform providing ephemeral or permanent inboxes and phone numbers for developers to verify sign-ups, OTPs, and notification delivery. It includes email preview across multiple clients, deliverability tracking, and REST APIs for integration into automated test workflows. It is indexed under Email Testing Dev.","source":"https://www.mailslurp.com","question":"What is MailSlurp?","confidence":0.6},{"answer":"MailSlurp offers a free tier, so you can start without paying. Pricing changes often, so verify at source before relying on it.","source":"https://www.mailslurp.com/compare/sendgrid-pricing/","question":"Is MailSlurp free?","confidence":0.6},{"answer":"We have confirmed browser-based access to MailSlurp. 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.mailslurp.com","question":"What platforms does MailSlurp support?","confidence":0.6},{"answer":"We have only confirmed a cloud / SaaS deployment for MailSlurp, so it appears to be vendor-hosted. If a self-hosted option exists we have not found it documented publicly.","source":"https://www.mailslurp.com","question":"Can MailSlurp be self-hosted?","confidence":0.6},{"answer":"We have confirmed 12 integrations for MailSlurp, including Zapier, Gmail, Outlook, Dropbox, Google Drive, Playwright, CypressJS and ACCELQ, plus 4 more. This is what we could verify from public sources, so the vendor may support others we have not indexed.","source":"https://www.mailslurp.com","question":"What does MailSlurp integrate with?","confidence":0.6},{"answer":"We have independently confirmed SOC 2 for MailSlurp. Certifications we do not list are ones we have not been able to verify from public sources, which is not the same as MailSlurp not holding them. Always confirm compliance directly before you rely on it.","source":"https://www.mailslurp.com","question":"What security certifications does MailSlurp have?","confidence":0.48}]` |
| deployment.options | `{"self_hosted":true}` | `{"cloud":true}` |
| description.long | 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. | MailSlurp is a cloud-based service that allows developers to create test email addresses and phone numbers, preview emails on real devices, validate message delivery, extract data from messages, and build automated messaging workflows through REST APIs and SDKs. |
| features.capabilities | `{"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}` | `{"open_source":false,"sms_testing":true,"api_assertions":true,"spam_score_check":true,"ci_cd_integration":true,"rendering_preview":true,"multi_user_inboxes":true,"production_sending_addon":true,"blocklist_deliverability_check":true}` |
| integrations.count | - | 8 |
| integrations.list | - | `[{"name":"Zapier"},{"name":"Gmail"},{"name":"Outlook"},{"name":"Dropbox"},{"name":"Google Drive"},{"name":"Playwright"},{"name":"CypressJS"},{"name":"ACCELQ"},{"name":"Mailchimp","native":true,"category":"email_marketing","direction":"inbound"},{"name":"Klaviyo","native":true,"category":"email_marketing","direction":"inbound"},{"name":"HubSpot","native":true,"category":"crm","direction":"inbound"},{"name":"Salesforce","native":true,"category":"crm","direction":"inbound"},{"name":"Cypress","native":true},{"name":"Selenium","native":true}]` |
| language.primary | Java | - |
| license.spdx | Apache-2.0 | - |
| platform.support | - | `{"web":true}` |
| pricing | `{"type":"open_source","freeTier":true,"sourceUrl":"https://greenmail-mail-test.github.io/greenmail/","retrievedAt":"2026-10-13T22:35:44.503Z"}` | `{"type":"free","freeTier":true,"sourceUrl":"https://www.mailslurp.com/compare/litmus-pricing/","retrievedAt":"2026-10-12T16:13:40.324Z"}` |
| pricing.free_tier | yes | yes |
| pricing.model | open_source | free |
| pricing.price_level | free | free |
| pricing.transparent | - | no |
| 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"}]` | - |
| security.gdpr | - | yes |
| security.scorecard | 6.6 | - |
| security.soc2 | - | yes |
| security.trust_center | - | https://www.mailslurp.com/compliance/ |
| 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 | GreenMail | MailSlurp |
|---|:--:|:--:|
| **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 2026-10-16T19:28:22.778Z. "-" = undocumented, not absent.*