# Mozilla Thunderbird vs Spark Mail

| Attribute | Mozilla Thunderbird | Spark Mail |
|---|---|---|
| **vioscaleAI score** | 48.7 (44% (low)) | 53.2 (74% (medium)) |
| activity.commits_last_30d | 100 | - |
| adoption.dependent_repos | 0 | - |
| adoption.github_stars | 14,107 | - |
| content.faq | `[{"answer":"Thunderbird consolidates email, calendars, and contacts from multiple accounts into one interface. It runs on Windows, Mac, and Linux, is funded by user donations, and prioritizes privacy by never collecting personal data or serving advertisements. It is indexed under Email Clients.","source":"https://www.thunderbird.net","question":"What is Mozilla Thunderbird?","confidence":0.6},{"answer":"Mozilla Thunderbird offers a free tier, so you can start without paying. Pricing changes often, so verify at source before relying on it.","source":"https://www.thunderbird.net","question":"Is Mozilla Thunderbird free?","confidence":0.6},{"answer":"Mozilla Thunderbird supports Windows, macOS and Linux. Platforms we have not confirmed are simply not listed here rather than ruled out.","source":"https://www.thunderbird.net","question":"What platforms does Mozilla Thunderbird support?","confidence":0.6},{"answer":"Yes. Mozilla Thunderbird 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/thunderbird/thunderbird-android","question":"Is Mozilla Thunderbird open source?","confidence":0.95}]` | `[{"answer":"Spark Mail is an email client that streamlines email handling through automated inbox organization, team collaboration features, and AI-assisted capabilities, with synchronized access across multiple accounts and devices. It is indexed under Email Clients.","source":"https://sparkmailapp.com","question":"What is Spark Mail?","confidence":0.6},{"answer":"Spark Mail offers a free tier, so you can start without paying. Paid plans start at $10 per user per month. Prices are published openly on the vendor's own pricing page. Pricing changes often, so verify at source before relying on it.","source":"https://sparkmailapp.com/de/pricing-teams","question":"Is Spark Mail free?","confidence":0.6},{"answer":"Spark Mail supports Windows, macOS and iOS. Platforms we have not confirmed are simply not listed here rather than ruled out.","source":"https://sparkmailapp.com","question":"What platforms does Spark Mail support?","confidence":0.6},{"answer":"We have only confirmed a cloud / SaaS deployment for Spark Mail, so it appears to be vendor-hosted. If a self-hosted option exists we have not found it documented publicly.","source":"https://sparkmailapp.com","question":"Can Spark Mail be self-hosted?","confidence":0.6},{"answer":"We have confirmed 30 integrations for Spark Mail, including Asana, MeisterTask, TickTick, Todoist, Trello, 2Do, OmniFocus and Reminders, plus 22 more. This is what we could verify from public sources, so the vendor may support others we have not indexed.","source":"https://sparkmailapp.com","question":"What does Spark Mail integrate with?","confidence":0.6},{"answer":"We have independently confirmed SOC 2 and GDPR for Spark Mail. Certifications we do not list are ones we have not been able to verify from public sources, which is not the same as Spark Mail not holding them. Always confirm compliance directly before you rely on it.","source":"https://sparkmailapp.com/de/pricing-teams","question":"What security certifications does Spark Mail have?","confidence":0.6},{"answer":"Spark Mail is available worldwide. Its primary market is the United States.","source":"https://sparkmailapp.com","question":"Where is Spark Mail available?","confidence":0.75}]` |
| deployment.options | - | `{"cloud":true}` |
| description.long | Thunderbird consolidates email, calendars, and contacts from multiple accounts into one interface. It runs on Windows, Mac, and Linux, is funded by user donations, and prioritizes privacy by never collecting personal data or serving advertisements. | A cross-platform email application offering core email functionality for free, with advanced features and team collaboration available through premium plans. Includes AI-assisted email handling, calendar integration, and task management connectors. |
| features.capabilities | `{"pricing_model":"free_open_source","deployment_model":"local_direct_imap_client","generative_ai_llm_email_drafting":false,"unified_multi_account_inbox_view":true,"universal_imap_smtp_exchange_support":true}` | `{"pricing_model":"freemium","deployment_model":"cloud_synchronization_proxy","generative_ai_llm_email_drafting":true,"unified_multi_account_inbox_view":true,"split_inbox_ai_auto_categorization":true,"universal_imap_smtp_exchange_support":true}` |
| integrations.count | - | 20 |
| integrations.list | - | `[{"name":"Asana"},{"name":"MeisterTask"},{"name":"TickTick"},{"name":"Todoist"},{"name":"Trello"},{"name":"2Do"},{"name":"OmniFocus"},{"name":"Reminders"},{"name":"Things"},{"name":"Evernote"},{"name":"Instapaper"},{"name":"OneNote"},{"name":"Agenda"},{"name":"Bear"},{"name":"Notion"},{"name":"Box"},{"name":"Dropbox"},{"name":"Google Drive"},{"name":"OneDrive"},{"name":"GoTo Meeting"},{"name":"Zoom"},{"name":"Google Calendar"},{"name":"Outlook"},{"name":"Microsoft Teams"},{"name":"Gmail"},{"name":"Yahoo"},{"name":"AOL"},{"name":"Exchange"},{"name":"iCloud"},{"name":"HubSpot"},{"name":"Salesforce"}]` |
| language.primary | Kotlin | - |
| license.spdx | Apache-2.0 | - |
| market.availability | - | `{"primaryMarkets":["US"],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` |
| platform.support | `{"mac":true,"linux":true,"windows":true}` | `{"ios":true,"mac":true,"web":true,"android":true,"windows":true}` |
| pricing | `{"type":"free","summary":"Free, open-source. Free forever.","freeTier":true,"sourceUrl":"https://www.thunderbird.net","retrievedAt":"2026-08-21T12:42:28.376Z"}` | `{"type":"subscription","plans":[{"free":true,"name":"Free","summary":"Free","features":["Unlimited email accounts","Smart search","Smart notifications","Scheduled send","Snooze","Set aside","Mark as done","Swipe actions","Control center","Quick replies","Print emails","Dark mode","Mute threads","Templates","Third-party integrations","Link sharing"],"components":[{"kind":"fixed","amount":0,"period":"month","currency":"USD"}],"description":"Unlimited email accounts with core inbox management features","contactSales":false},{"free":false,"name":"Plus","summary":"$10/user/month or $120/year","features":["All Free features","Comprehensive mail productivity","Spark +AI (AI assistant)","Basic team collaboration","Custom templates","Productive integrations","5 lifetime meeting notes"],"components":[{"kind":"per_unit","unit":"user","amount":10,"period":"month","currency":"USD"},{"kind":"per_unit","unit":"user","amount":10,"period":"year","currency":"USD"}],"description":"For individuals and small teams needing email productivity tools","contactSales":false,"includedLimits":{"ai_meeting_notes":"5 lifetime"}},{"free":false,"name":"Pro","summary":"$20/user/month or $240/year","features":["All Plus features","Unlimited +AI meeting notes","Workflows","Automatic labels (coming soon)","Read status","Advanced team collaboration","HubSpot integration","Spark CLI with triage access","40 meeting notes per month"],"components":[{"kind":"per_unit","unit":"user","amount":20,"period":"month","currency":"USD"},{"kind":"per_unit","unit":"user","amount":20,"period":"year","currency":"USD"}],"description":"For professionals and teams with customer contact who need advanced features","contactSales":false,"includedLimits":{"ai_meeting_notes":"40 per month"}},{"free":false,"name":"Enterprise","summary":"Custom pricing - contact sales","features":["All Pro features","Security & control (SOC II compliance)","Dedicated customer success management","1:1 productivity coaching","Centralized billing","Team management"],"description":"For larger teams requiring enhanced security and support","contactSales":true}],"summary":"Free tier available. Plus $10/user/month, Pro $20/user/month (or annual billing). Enterprise custom pricing.","currency":"USD","freeTier":true,"sourceUrl":"https://sparkmailapp.com/de/pricing-teams","retrievedAt":"2026-08-20T14:05:07.204Z","freeTrialDays":7,"startingPrice":{"unit":"user","amount":10,"period":"month","currency":"USD"},"billingPeriods":["month","year"]}` |
| pricing.free_tier | yes | yes |
| pricing.model | freemium | freemium |
| pricing.price_level | free | low |
| pricing.starting_price | - | `{"amount":10,"currency":"USD"}` |
| pricing.transparent | yes | no |
| release.history | `[{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_24_0","date":"2026-10-05T23:38:09Z","type":"stable","version":"THUNDERBIRD_24_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_24_0","date":"2026-10-05T23:38:15Z","type":"stable","version":"K9MAIL_24_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_25_0b1","date":"2026-10-05T23:36:57Z","type":"prerelease","version":"THUNDERBIRD_25_0b1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_23_1","date":"2026-09-22T05:59:49Z","type":"stable","version":"THUNDERBIRD_23_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_23_1","date":"2026-09-22T05:59:50Z","type":"stable","version":"K9MAIL_23_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_24_0b2","date":"2026-09-14T18:09:35Z","type":"prerelease","version":"THUNDERBIRD_24_0b2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_23_0","date":"2026-09-09T06:41:45Z","type":"stable","version":"THUNDERBIRD_23_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_23_0","date":"2026-09-09T06:41:39Z","type":"stable","version":"K9MAIL_23_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_24_0b1","date":"2026-09-08T22:28:10Z","type":"prerelease","version":"THUNDERBIRD_24_0b1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_22_0","date":"2026-08-11T03:59:18Z","type":"stable","version":"THUNDERBIRD_22_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_22_0","date":"2026-08-11T03:59:18Z","type":"stable","version":"K9MAIL_22_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_23_0b1","date":"2026-08-10T22:13:14Z","type":"prerelease","version":"THUNDERBIRD_23_0b1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_21_1","date":"2026-08-03T19:14:04Z","type":"stable","version":"THUNDERBIRD_21_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_21_1","date":"2026-08-03T19:14:10Z","type":"stable","version":"K9MAIL_21_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_22_0b2","date":"2026-07-27T20:45:48Z","type":"prerelease","version":"THUNDERBIRD_22_0b2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_21_0","date":"2026-07-20T21:30:00Z","type":"stable","version":"THUNDERBIRD_21_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_21_0","date":"2026-07-20T21:29:55Z","type":"stable","version":"K9MAIL_21_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_22_0b1","date":"2026-07-20T23:20:30Z","type":"prerelease","version":"THUNDERBIRD_22_0b1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_20_1","date":"2026-07-06T22:30:54Z","type":"stable","version":"THUNDERBIRD_20_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_20_1","date":"2026-07-06T22:30:53Z","type":"stable","version":"K9MAIL_20_1"}]` | - |
| security.gdpr | - | yes |
| security.scorecard | 7.2 | - |
| security.soc2 | - | yes |
| security.trust_center | - | https://sparkmailapp.com/blog/privacy-explained |
| security.vulnerabilities | `{"count":0,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=fdroid&package_name=com.fsck.k9&per_page=100","last_12m":0,"max_severity":null}` | - |

## Capabilities (Email Clients)

| Capability | Mozilla Thunderbird | Spark Mail |
|---|:--:|:--:|
| **Capabilities** |  |  |
| Deployment model | Local direct imap client | Cloud synchronization proxy |
| Universal imap smtp exchange support | ✓ | ✓ |
| Keyboard shortcut only navigation speed | - | - |
| Split inbox AI auto categorization | - | ✓ |
| Read receipts and open tracking | - | - |
| Snooze and scheduled send later | - | - |
| Generative AI LLM email drafting | ✗ | ✓ |
| Conversational chat layout view | - | - |
| Unified multi account inbox view | ✓ | ✓ |
| Pgp end to end encryption support | - | - |
| SOC2 type ii | - | - |
| ISO 27001 | - | - |
| Pricing model | Free open source | Freemium |

*Source: vioscaleAI. Generated 2026-10-16T18:31:42.596Z. "-" = undocumented, not absent.*