# Mailspring vs Mozilla Thunderbird

| Attribute | Mailspring | Mozilla Thunderbird |
|---|---|---|
| **Vioscale score** | 66.3 (29% (low)) | 60.1 (27% (low)) |
| activity.commits_last_30d | 38 | 100 |
| adoption.dependent_repos | - | 0 |
| adoption.github_stars | 17,762 | 13,921 |
| description.long | A lightweight desktop application for Mac, Windows, and Linux that brings together multiple email accounts from different providers into one unified inbox. Core features run locally on your computer, with optional paid features for message tracking, scheduling, and productivity analytics. | 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. |
| features.capabilities | `{"pricing_model":"freemium","deployment_model":"local_direct_imap_client","read_receipts_and_open_tracking":true,"snooze_and_scheduled_send_later":true,"unified_multi_account_inbox_view":true,"universal_imap_smtp_exchange_support":true}` | `{"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}` |
| integrations.count | 7 | - |
| integrations.list | `[{"name":"Gmail"},{"name":"iCloud"},{"name":"Office 365"},{"name":"FastMail"},{"name":"Outlook.com"},{"name":"Yahoo!"},{"name":"IMAP"},{"name":"SMTP"}]` | - |
| language.primary | JavaScript | Kotlin |
| license.spdx | GPL-3.0 | Apache-2.0 |
| market.availability | `{"primaryMarkets":[],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` | - |
| platform.support | `{"mac":true,"linux":true,"windows":true}` | `{"mac":true,"linux":true,"windows":true}` |
| pricing | `{"type":"freemium","plans":[{"free":true,"name":"Free","features":["Multi-account support","Unified inbox","Snooze","Send later","Mail rules","Templates","Grammar and spell checking","Translation support","Follow-up reminders"],"description":"Multi-account email client with unified inbox, local sync, and productivity features","contactSales":false},{"free":false,"name":"Pro","summary":"$8/month","features":["Read receipts","Link tracking","Unlimited snooze and send later","Mailbox analytics","Contact and company profiles"],"components":[{"kind":"fixed","amount":8,"period":"month","currency":"USD"}],"description":"Adds message tracking and unlimited scheduling features","contactSales":false}],"summary":"Free tier available; Pro at $8/month","currency":"USD","freeTier":true,"sourceUrl":"https://getmailspring.com","retrievedAt":"2026-08-21T12:46:43.649Z","startingPrice":{"amount":8,"period":"month","currency":"USD"},"billingPeriods":["month"]}` | `{"type":"free","summary":"Free, open-source. Free forever.","freeTier":true,"sourceUrl":"https://www.thunderbird.net","retrievedAt":"2026-08-21T12:42:28.376Z"}` |
| pricing.free_tier | yes | yes |
| pricing.model | commercial | freemium |
| pricing.price_level | low | free |
| pricing.starting_price | `{"amount":8,"currency":"USD"}` | - |
| pricing.transparent | yes | yes |
| release.cadence_days | 15 | - |
| release.history | `[{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.23.0","date":"2026-07-22T03:45:22Z","type":"stable","version":"1.23.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.22.0","date":"2026-06-13T20:30:13Z","type":"stable","version":"1.22.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.21.1","date":"2026-05-20T20:31:26Z","type":"stable","version":"1.21.1"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.21.0","date":"2026-05-06T13:40:43Z","type":"stable","version":"1.21.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.20.1","date":"2026-04-20T16:07:46Z","type":"stable","version":"1.20.1"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.20.0","date":"2026-04-19T03:40:03Z","type":"stable","version":"1.20.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.19.1","date":"2026-04-07T01:34:03Z","type":"stable","version":"1.19.1"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.19.0","date":"2026-03-10T04:46:53Z","type":"stable","version":"1.19.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.18.0","date":"2026-02-23T14:40:58Z","type":"stable","version":"1.18.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.17.4","date":"2026-02-11T16:59:03Z","type":"stable","version":"1.17.4"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.17.3","date":"2026-01-31T20:21:11Z","type":"stable","version":"1.17.3"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.17.2","date":"2026-01-24T21:09:28Z","type":"stable","version":"1.17.2"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.17.1","date":"2026-01-15T20:55:25Z","type":"stable","version":"1.17.1"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.17.0","date":"2026-01-14T22:33:16Z","type":"stable","version":"1.17.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.16.0","date":"2025-07-16T14:29:44Z","type":"stable","version":"1.16.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.15.1","date":"2025-01-27T00:52:05Z","type":"stable","version":"1.15.1"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.15.0","date":"2025-01-02T15:25:00Z","type":"stable","version":"1.15.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.14.0","date":"2024-09-15T00:35:52Z","type":"stable","version":"1.14.0"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.13.3","date":"2024-01-08T19:59:00Z","type":"stable","version":"1.13.3"},{"url":"https://github.com/Foundry376/Mailspring/releases/tag/1.13.2","date":"2023-12-11T02:31:01Z","type":"stable","version":"1.13.2"}]` | `[{"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"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_21_0b2","date":"2026-06-29T21:12:45Z","type":"prerelease","version":"THUNDERBIRD_21_0b2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_20_0","date":"2026-06-23T01:45:10Z","type":"stable","version":"K9MAIL_20_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_20_0","date":"2026-06-23T01:45:03Z","type":"stable","version":"THUNDERBIRD_20_0"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_21_0b1","date":"2026-06-22T17:24:23Z","type":"prerelease","version":"THUNDERBIRD_21_0b1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_19_2","date":"2026-06-04T19:32:37Z","type":"stable","version":"THUNDERBIRD_19_2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_19_2","date":"2026-06-04T19:32:32Z","type":"stable","version":"K9MAIL_19_2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_20_0b2","date":"2026-06-04T18:27:10Z","type":"prerelease","version":"THUNDERBIRD_20_0b2"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/THUNDERBIRD_19_1","date":"2026-06-03T22:11:56Z","type":"stable","version":"THUNDERBIRD_19_1"},{"url":"https://github.com/thunderbird/thunderbird-android/releases/tag/K9MAIL_19_1","date":"2026-06-03T22:11:55Z","type":"stable","version":"K9MAIL_19_1"}]` |
| security.scorecard | - | 7.2 |
| 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 | Mailspring | Mozilla Thunderbird |
|---|:--:|:--:|
| **Capabilities** |  |  |
| Deployment model | Local direct imap client | Local direct imap client |
| 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 | Freemium | Free open source |

*Source: Vioscale. Generated 2026-09-01T14:39:23.970Z. "-" = undocumented, not absent.*