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Best K-9 Mail Alternatives in 2026

Updated

20 platforms from email clients ranked against K-9 Mail on the same published basis.

  1. 1
    Mozilla Thunderbird Free plan Open sourceAndroidLinuxMacWin Free8.3
    K-9 Mail vs Mozilla Thunderbird
  2. 2
    Hiver api $25/mo8.1
    K-9 Mail vs Hiver
  3. 3
    Front api $25/mo8.0
    K-9 Mail vs Front
  4. 4
    Gmelius Free trial AndroidapiextensioniOSWeb $19/mo7.8
    K-9 Mail vs Gmelius
  5. 5
    Zoho Mail Free plan AndroidiOSLinuxMacWeb $0.08/mo7.5
    K-9 Mail vs Zoho Mail
  6. 6
    Spark Mail Free plan AndroidiOSMacWin $8.25/mo7.5
    K-9 Mail vs Spark Mail
  7. 7
    eM Client Free plan AndroidiOSMacWin $3.33/mo7.5
    K-9 Mail vs eM Client
  8. 8
    Mailspring Free plan LinuxMacWin 7.4
    K-9 Mail vs Mailspring
  9. 9
    Newton Mail Free plan AndroidiOSMacWin $5/mo7.3
    K-9 Mail vs Newton Mail
  10. 10
    Spike Free plan AndroidiOSMacWebWin $4/mo7.3
    K-9 Mail vs Spike
  11. 11
    Canary Mail Free plan AndroidiOSMacWin $3/mo7.3
    K-9 Mail vs Canary Mail
  12. 12
    Mailbutler Smart Assistant Free plan AndroidextensioniOSLinuxMac $7/mo7.3
    K-9 Mail vs Mailbutler Smart Assistant
  13. 13
    Airmail Free plan iOSMac $2.50/mo7.2
    K-9 Mail vs Airmail
  14. 14
    Mailpile Free plan apiLinuxMacself-hostedWeb Free7.2
    K-9 Mail vs Mailpile
  15. 15
    Epistles Mail Free plan AndroidiOSLinuxMacWeb $2.92/mo7.1
    K-9 Mail vs Epistles Mail
  16. 16
    Velo Free plan WinMacLinux Free6.9
    K-9 Mail vs Velo
  17. 17
    KMail Linux 6.8
    K-9 Mail vs KMail
  18. 18
    Missive WebWinMaciOSAndroid $14/mo6.8
    K-9 Mail vs Missive
  19. 19
    Dove Free plan WebWinMaciOSAndroid $20/mo6.8
    K-9 Mail vs Dove
  20. 20
    EmailOps Free plan LinuxMacWin Free6.8
    K-9 Mail vs EmailOps

K-9 Mail alternatives compared

#PlatformScoreFree planFromRuns on
1Mozilla Thunderbird8.3Free planFreeAndroid, Linux, Mac, Windows
2Hiver8.1No$25/moAPI
3Front8.0No$25/moAPI
4Gmelius7.8No$19/moAndroid, API, Browser, iOS, Web
5Zoho Mail7.5Free plan$0.08/moAndroid, iOS, Linux, Mac, Web, Windows
6Spark Mail7.5Free plan$8.25/moAndroid, iOS, Mac, Windows
7eM Client7.5Free plan$3.33/moAndroid, iOS, Mac, Windows
8Mailspring7.4Free plan—Linux, Mac, Windows
9Newton Mail7.3Free plan$5/moAndroid, iOS, Mac, Windows
10Spike7.3Free plan$4/moAndroid, iOS, Mac, Web, Windows
11Canary Mail7.3Free plan$3/moAndroid, iOS, Mac, Windows
12Mailbutler Smart Assistant7.3Free plan$7/moAndroid, Browser, iOS, Linux, Mac, Web, Windows
13Airmail7.2Free plan$2.50/moiOS, Mac
14Mailpile7.2Free planFreeAPI, Linux, Mac, self-hosted, Web, Windows
15Epistles Mail7.1Free plan$2.92/moAndroid, iOS, Linux, Mac, Web, Windows
16Velo6.9Free planFreeWindows, Mac, Linux
17KMail6.8No—Linux
18Missive6.8No$14/moWeb, Windows, Mac, iOS, Android
19Dove6.8Free plan$20/moWeb, Windows, Mac, iOS, Android
20EmailOps6.8Free planFreeLinux, Mac, Windows
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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 8.3 out of 10. The others here: Hiver, Front, Gmelius and 16 more.

What is the best free alternative to K-9 Mail?

Mozilla Thunderbird is the best-ranked alternative with a free plan. 15 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 on what each maker publishes, open and connectable first: a public API, open-source code, the depth of its documentation and a free tier to try it on. Model lists are sorted by the figure in their title, exactly as each provider publishes it.