DeveloperThe Calyx Institute
OS familyUnix-like (Android)
Source modelOpen source with proprietary components[citation needed]
Update methodOver-the-air (OTA), ROM flashing
Package managerAPK-based
Platformsarm, arm64

CalyxOS is an operating system for smartphones based on Android with mostly free and open-source software. It is produced by the Calyx Institute as part of its mission to "defend online privacy, security and accessibility."[1]

CalyxOS preserves the Android security model, using Android's Verified Boot system of cryptographic signing of the operating system, and running with a locked bootloader,[2][3] partly thanks to an installer that guides the user through the process of unlocking and then re-locking the bootloader.[4]


The Calyx Institute annual reports[5] state CalyxOS was publicly launched during their 2018–2019 fiscal year. Inspiration included Tails and Qubes OS, and goals were said to be "completely open source", removing proprietary Google tracking, and including apps Tor, Signal and CalyxVPN for increased privacy.[6]

CalyxOS supports Pixel phones Pixel 3 and newer.[7] In April 2022, CalyxOS announced Android 12L for testing on Fairphone 4, and OnePlus 8T, 9, and 9 Pro.[8] However, in May 2022, CalyxOS announced OnePlus builds were pulled because of a bootloader "relock issue".[9] As of July 2022, according to CalyxOS the OnePlus relock issue had not been resolved.[10]


This list is incomplete; you can help by adding missing items. (September 2022)


Feature(s) Notes
Aurora Store Alternative to the standard Google Play Store Aurora Store uses the same standard catalog of apps and installs apps directly from the Google servers to phone.[11][12] CalyxOS gives Aurora Store special privileges so that app updates can be automatically installed.
Chromium FOSS web browser Bromite fork, succeeded DuckDuckGo mobile browser as the default web browser in June 2022.[13]
F-Droid Repository of FOSS applications for the Android platform CalyxOS gives F-Droid special privileges to streamline app updates, installs, and uninstalls.[11][14]
MicroG FOSS implementation of proprietary Google Play Services Some apps dependent on Google Play Services may not work with MicroG, use of MicroG is optional.[11][15]
Organic Maps Navigation app with privacy Privacy-focused navigation app for driving, hiking, and cycling. Search for locations and navigate without a cell phone signal. [16]
Seedvault Encrypted backup and restore application for Android The Calyx Institute sponsored development of SeedVault [17] and an annual report states they "debuted SeedVault" during their 2019-2020 fiscal year.[18]

SeedVault is also used by LineageOS.[19][20]

Signal Encrypted calling/messaging app Free, privacy-focused messaging and voice talk app, preinstalled as messaging app in CalyxOS.[11][21]

CalyxOS ships with MicroG as an open-source alternative to the Google Mobile Services, including Mozilla Location Services as an optional replacement to the location services provided by Google, but gives the user the option to disable microG and its location services.[22]


In October 2020, Moritz Tremmel reviewed CalyxOS.[23] A month later, Tremmel explained why he preferred CalyxOS over LineageOS.[24] A year later in September 2021, Tremmel further explained how CalyxOS was different from other ROMs because it did not require as much "fiddling".[25] Rahul Nambiampurath, writing for MakeUseOf in March 2021, termed CalyxOS, "[one of the] best [Android] ROMs for privacy ... offers the perfect middle ground between convenience and privacy".[26] In August 2021, Android Authority wrote CalyxOS "puts privacy and security into the hands of everyday users."[27]

In 2022, the book c't Sicher ins Netz: How to block out monitors and attackers, said "CalyxOS is one of the youngest custom ROMs, it will only celebrate its second birthday in summer 2022. With a built-in Datura firewall, VPN and Cloudflare DNS, Calyx promises more security than some other mobile systems."[28]

In 2023, CalyxOS was the one alternative phone operating system recommended by Carey Parker in the book "Firewalls Don't Stop Dragons".[29]

In a review in February 2023, the Kuketz Security blog said CalyxOS "offers a coherent overall package that should give users who want to (strongly) reduce their dependency on Google a good start" and said the integrated Datura Firewall works well. However, it criticized some previous delayed security updates and said the website does not "quite match what the present analysis revealed" regarding the information given to Google.[30]


  1. ^ "About The Calyx Institute - Calyx Institute". Retrieved 2021-11-02.
  2. ^ "Security FAQ". Retrieved 2023-03-03.
  3. ^ "Android Security Bulletins". Retrieved 2023-03-03.
  4. ^ "CalyxOS: Google-freies Android". Linux-Magazin (in German). Retrieved 2023-04-13. Bei der Installation wird auch der Geräteschlüssel von Google gegen einen von CalyxOS ausgetauscht. Das ermöglicht einen verifizierten Bootvorgang und stellt sicher, dass sich nur von CalyxOS signierte Updates installieren lassen. Um den Schutz zu aktivieren, fragt der Installer am Schluss, ob er den Bootloader wieder sperren soll, was es zu bestätigen gilt. Anschließend ist die CalyxOS-Installation startklar.
  5. ^ "Financials and Annual Reports - Calyx Institute". Retrieved 2022-07-26.
  6. ^ "Annual Report 2018-2019" (PDF). Archived from the original on 2022-07-26. Retrieved 2022-09-19.((cite web)): CS1 maint: bot: original URL status unknown (link)
  7. ^ "CalyxOS". Retrieved 2022-07-30.
  8. ^ "Fairphone 4, OnePlus 8T, OnePlus 9 test builds now available". Retrieved 2022-07-30.
  9. ^ "May 2022 Security update - Fairphone 4, OnePlus 8T, 9, 9 Pro". Retrieved 2022-07-30.
  10. ^ "OnePlus Android 12 firmware - relocking no longer works". Retrieved 2022-07-30.
  11. ^ a b c d Cite error: The named reference :0 was invoked but never defined (see the help page).
  12. ^ "Aurora Store". Retrieved 2022-09-29.
  13. ^ "June 2022 Security update - Pixels". Archived from the original on 2022-10-25.
  14. ^ "F-Droid". Retrieved 2022-09-29.
  15. ^ "microG". Retrieved 2022-08-01.
  16. ^ "Organic Maps: Offline Hike, Bike, Trails and Navigation". Retrieved 2023-08-24.
  17. ^ "SeedVault - Calyx Institute". Retrieved 2022-07-23.
  18. ^ "Annual Report 2019-2020" (PDF). Archived from the original on 2022-07-26. Retrieved 2022-09-19.((cite web)): CS1 maint: bot: original URL status unknown (link)
  19. ^ Hazarika, Skanda (November 4, 2020). "LineageOS adopts SeedVault as its open source backup solution". XDA Developers.
  20. ^ Hazarika, Skanda (2021-03-31). "LineageOS 18.1 based on Android 11 is here for nearly 60 devices". XDA Developers. Retrieved 2023-04-13.
  21. ^ "Signal". Retrieved 2022-09-29.
  22. ^ "5 De-Googled Android-based Operating Systems". It's FOSS. 2021-11-13. Retrieved 2023-04-13. Instead of not shipping the Google Mobile Services (GMS) and leaving users to figure stuff out by themselves (flashing gapps etc), CalyxOS ships with microG. However, you can choose to enable/disable it, thus, giving you total control. [...] Uses Mozilla Location Services instead of Google's Location Services
  23. ^ Moritz Tremmel (2020-10-19). "CalyxOS im Test: Ein komfortables Android mit einer Extraportion Privacy". (in German). Retrieved 2021-02-02.
  24. ^ Tremmel, Moritz (November 10, 2020). "Bye-bye, Lineage OS!". (in German). Archived from the original on 2020-11-12. Retrieved 2021-11-02.
  25. ^ Tremmel, Moritz. "CalyxOS: Google-freies Android". Linux-Magazin (in German). Retrieved 2021-11-02.
  26. ^ "What's the Best Privacy-Focussed Android ROM?". MUO. 2021-03-29. Retrieved 2021-11-02.
  27. ^ "Gary Explains: Linux turns 30, Tesla's D1 chip, Power⚡️ over Ethernet & more!". Android Authority. Retrieved 2021-11-02.
  28. ^ c't-Redaktion (2022-05-18). c't Sicher ins Netz: So sperren Sie Überwacher und Angreifer aus (in German). Heise Medien GmbH & Co. KG. ISBN 978-3-95788-313-1.
  29. ^ Parker, Carey (2023), Parker, Carey (ed.), "Odds and Ends", Firewalls Don't Stop Dragons: A Step-by-Step Guide to Computer Security and Privacy for Non-Techies, Berkeley, CA: Apress, pp. 541–558, doi:10.1007/978-1-4842-9036-1_13, ISBN 978-1-4842-9036-1, retrieved 2023-04-13
  30. ^ Kuketz, Mike (February 10, 2023). "CalyxOS: De-Googled geht anders – Custom-ROMs Teil2". Kuketz IT-Security blog. Retrieved February 11, 2023.((cite web)): CS1 maint: url-status (link)

See also