# Email on Acid vs Maildev

| Attribute | Email on Acid | Maildev |
|---|---|---|
| **Vioscale score** | 58.3 (66% (medium)) | 63.8 (24% (low)) |
| activity.commits_last_30d | - | 24 |
| adoption.dependent_repos | - | 313 |
| adoption.github_stars | - | 6,032 |
| 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. | Runs as a local SMTP server with a web inbox interface to capture and review emails generated by your application during development. Supports AI agent integration through the Model Context Protocol for automated email inspection. |
| 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}` | - |
| language.primary | - | TypeScript |
| license.spdx | - | MIT |
| market.availability | `{"primaryMarkets":["US"],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` | - |
| platform.support | `{"web":true}` | `{"cli":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"]}` | `{"type":"free","summary":"Free & open source (MIT)","freeTier":true,"sourceUrl":"https://maildev.github.io/maildev/","retrievedAt":"2026-08-20T16:30:07.523Z"}` |
| pricing.free_tier | no | yes |
| pricing.model | commercial | commercial |
| pricing.price_level | high | free |
| pricing.starting_price | `{"amount":99,"currency":"USD"}` | - |
| pricing.transparent | yes | yes |
| release.cadence_days | - | 46 |
| release.history | - | `[{"url":"https://github.com/maildev/maildev/releases/tag/maildev%403.0.0-rc.1","date":"2026-07-06T19:40:50Z","type":"stable","version":"maildev@3.0.0-rc.1"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.2.1","date":"2024-12-12T02:09:20Z","type":"stable","version":"v2.2.1"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.1.0","date":"2023-07-20T01:57:33Z","type":"stable","version":"v2.1.0"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.0.5","date":"2022-05-18T16:10:38Z","type":"stable","version":"v2.0.5"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.0.4","date":"2022-05-17T21:24:00Z","type":"stable","version":"v2.0.4"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.0.2","date":"2022-03-23T07:56:47Z","type":"stable","version":"v2.0.2"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.0.1","date":"2022-03-23T03:43:18Z","type":"stable","version":"v2.0.1"},{"url":"https://github.com/maildev/maildev/releases/tag/v2.0.0","date":"2022-03-22T16:22:09Z","type":"stable","version":"v2.0.0"},{"url":"https://github.com/maildev/maildev/releases/tag/v1.1.1","date":"2022-03-22T16:08:54Z","type":"stable","version":"v1.1.1"},{"url":"https://github.com/maildev/maildev/releases/tag/v1.1.0","date":"2019-07-27T21:57:24Z","type":"stable","version":"v1.1.0"},{"url":"https://github.com/maildev/maildev/releases/tag/1.0.0","date":"2019-03-19T02:36:24Z","type":"stable","version":"1.0.0"},{"url":"https://github.com/maildev/maildev/releases/tag/0.14.0","date":"2016-08-13T16:24:32Z","type":"stable","version":"0.14.0"},{"url":"https://github.com/maildev/maildev/releases/tag/0.13.4","date":"2016-07-01T22:58:28Z","type":"stable","version":"0.13.4"},{"url":"https://github.com/maildev/maildev/releases/tag/0.13.3","date":"2016-05-16T04:11:12Z","type":"stable","version":"0.13.3"},{"url":"https://github.com/maildev/maildev/releases/tag/0.13.2","date":"2016-05-14T18:25:02Z","type":"stable","version":"0.13.2"},{"url":"https://github.com/maildev/maildev/releases/tag/0.13.1","date":"2016-04-22T03:17:26Z","type":"stable","version":"0.13.1"},{"url":"https://github.com/maildev/maildev/releases/tag/0.13.0","date":"2016-03-20T20:45:31Z","type":"stable","version":"0.13.0"},{"url":"https://github.com/maildev/maildev/releases/tag/0.12.2","date":"2016-03-08T03:05:13Z","type":"stable","version":"0.12.2"},{"url":"https://github.com/maildev/maildev/releases/tag/0.12.1","date":"2015-11-07T23:18:35Z","type":"stable","version":"0.12.1"},{"url":"https://github.com/maildev/maildev/releases/tag/0.12.0","date":"2015-08-26T04:51:51Z","type":"stable","version":"0.12.0"}]` |
| reliability.sla_pct | 99.9 | - |
| security.gdpr | yes | - |
| security.iso27001 | yes | - |
| security.scorecard | - | 4.6 |
| security.soc2 | yes | - |
| security.vulnerabilities | - | `{"count":1,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=npm&package_name=maildev&per_page=100","last_12m":0,"max_severity":"CRITICAL"}` |

## Capabilities (Email Testing Dev)

| Capability | Email on Acid | Maildev |
|---|:--:|:--:|
| **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 2026-09-01T14:46:42.685Z. "-" = undocumented, not absent.*