Best K-9 Mail Alternatives in 2026
Updated
20 apps from email clients ranked against K-9 Mail on the same published basis.
- 1K-9 Mail vs Mozilla Thunderbird
- 2K-9 Mail vs Zoho Mail
- 3K-9 Mail vs Spark Mail
- 4K-9 Mail vs eM Client
- 5K-9 Mail vs Newton Mail
- 6K-9 Mail vs Spike
- 7K-9 Mail vs Canary Mail
- 8K-9 Mail vs Mailbutler Smart Assistant
- 9K-9 Mail vs Airmail
- 10K-9 Mail vs FairEmail
- 11K-9 Mail vs Epistles Mail
- 12K-9 Mail vs Dove
- 13K-9 Mail vs Saymail
- 14K-9 Mail vs Apple Mail
- 15K-9 Mail vs Missive
- 16K-9 Mail vs BlueMail
- 17K-9 Mail vs Polymail
- 18K-9 Mail vs Workspace ONE Boxer
- 19K-9 Mail vs Twobird
- 20K-9 Mail vs Superhuman Mail
K-9 Mail alternatives compared
| # | App | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 1 | Mozilla Thunderbird | 9.7 | Free plan | Free | Android, Linux, Mac, Windows |
| 2 | Zoho Mail | 9.7 | Free plan | $0.08/mo | Android, iOS, Linux, Mac, Web, Windows |
| 3 | Spark Mail | 9.7 | Free plan | $8.25/mo | Android, iOS, Mac, Windows |
| 4 | eM Client | 9.7 | Free plan | $3.33/mo | Android, iOS, Mac, Windows |
| 5 | Newton Mail | 9.5 | Free plan | $5/mo | Android, iOS, Mac, Windows |
| 6 | Spike | 9.5 | Free plan | $4/mo | Android, iOS, Mac, Web, Windows |
| 7 | Canary Mail | 9.4 | Free plan | $3/mo | Android, iOS, Mac, Windows |
| 8 | Mailbutler Smart Assistant | 9.4 | Free plan | $7/mo | Android, Browser, iOS, Linux, Mac, Web, Windows |
| 9 | Airmail | 9.3 | Free plan | $2.50/mo | iOS, Mac |
| 10 | FairEmail | 9.3 | Free plan | Free | Android |
| 11 | Epistles Mail | 9.3 | Free plan | $2.92/mo | Android, iOS, Linux, Mac, Web, Windows |
| 12 | Dove | 9.0 | Free plan | $16.67/mo | Android, iOS, Mac, Web, Windows |
| 13 | Saymail | 8.9 | Free plan | €3.25/mo | Windows, Mac, Linux, iOS, Android |
| 14 | Apple Mail | 8.7 | No | — | Mac, iOS |
| 15 | Missive | 8.7 | No | $14/mo | Web, Windows, Mac, iOS, Android |
| 16 | BlueMail | 8.7 | No | — | Windows, Mac, Linux, iOS, Android |
| 17 | Polymail | 8.6 | No | $10/mo | Web, Windows, Mac, iOS |
| 18 | Workspace ONE Boxer | 8.6 | No | $5.40/mo | Web, Windows, Mac, Linux, iOS, Android |
| 19 | Twobird | 8.6 | Free plan | Free | Web, Windows, Mac, iOS, Android |
| 20 | Superhuman Mail | 8.5 | No | $2.08/mo | Web, Windows, Mac, iOS, Android |
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Questions about K-9 Mail alternatives
What is the best alternative to K-9 Mail?
Mozilla Thunderbird, number 1 in email clients with a score of 9.7 out of 10. The others here: Zoho Mail, Spark Mail, eM Client and 16 more.
What is the best free alternative to K-9 Mail?
Mozilla Thunderbird is the best-ranked alternative with a free plan. 14 of the 20 alternatives here publish a free plan on their own pricing pages.
Is there an open-source alternative to K-9 Mail?
Yes: Mozilla Thunderbird.
How are these alternatives ranked?
Ranked mobile-first: a phone app alongside the web or desktop product, a free tier and the depth of its documentation.