Zephyr RTOS
Hacker ApprovedRanked 2 of 6 real-time operating systems by recommenders
Recommended for broad board support, strong wireless and networking stacks, and a portable HAL. Critics mainly point to flash chip power management problems.
Recommended for broad board support, strong wireless and networking stacks, and a portable HAL. Critics mainly point to flash chip power management problems.
19 people gave an opinion
- recommend it
- 14
- criticize it
- 5
- approval share
- 74%
Recommended in 11 of 13 months
- November 2025: recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: not recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 14 people recommend itNeeds 10 or more, met.
- 2.8 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 11 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Strong wireless and networking stacks
“an extremely capable RTOS with a decent shell, good features, and one of the best RTOS networking stacks out there”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” “Zephyr blows away Arduino, it has portable stacks, security, update, wifi/ble, etc...”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” “zephyr seems to be the embedded os with the best wireless support by a country mile”
Comment from 29 Jul 2026 in “The Rust on ESP Book” - Comment from 7 Jun 2026 in “Porting Zircon (Fuchsia OS's kernel) C++ code to Rust”
- Comment from 4 Mar 2026 in “Libre Solar – Open Hardware for Renewable Energy”
Supported on boards from many vendors
“Their HAL works, their stacks work, the portability is incredibly smooth compared to other vendors.”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” “Come over to Zephyr and see all the stuff you can run on boards from basically everyone”
Comment from 14 Jan 2026 in “SparkFun Officially Dropping AdaFruit due to CoC Violation” “every major embedded SOC/MCU maker supports it”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” - Comment from 3 Sep 2026 in “Async Rust vs RTOS showdown (2022)”
Portable HAL that works well
“Their HAL works, their stacks work, the portability is incredibly smooth compared to other vendors.”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” “Zephyr blows away Arduino, it has portable stacks, security, update, wifi/ble, etc...”
Comment from 20 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” “Zephyr's HAL streamlines the latter. Very nice.”
Comment from 21 Dec 2025 in “Arduino UNO Q bridges high-performance computing with real-time control” Pragmatic choice for most embedded
“10 years on a project then a full rewrite to zephyr - thats the move”
Comment from 23 Apr 2026 in “Show HN: OpenDeck – DIY MIDI Platform Based on Zephyr RTOS” “Zephyr/C seema still the pragmatic choice for most embedded”
Comment from 3 Sep 2026 in “Async Rust vs RTOS showdown (2022)”
Other real-time operating systems people recommend
The four most recommended other real-time operating systems, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| QNX Neutrino RTOS | 47 | 12 | 80% | 12 | 10 yrs3 owners | Approved |
| Zephyr RTOSThis page | 14 | 5 | 74% | 11 | — | Approved |
| FreeRTOS | 9 | 3 | 75% | 6 | — | — |
| Hubris RTOS | 6 | 0 | 100% | 6 | — | — |
| MicroPythonOS | 6 | 4 | 60% | 1 | — | — |
What people said
22 of the 23 comments that mention it, newest first. Each links to the original comment.
“You compile it and your application together and get a binary.”
“There isn't a single embedded OS FOSS alternative to GNU/Linux that uses GPL, including Linux Foundation's own Zephyr.”
“Zephyr/C seema still the pragmatic choice for most embedded”
“Every vendor on earth now supports it”
“zephyr seems to be the embedded os with the best wireless support by a country mile”
“amazing ecosystem of fantastic wireless connectivity offerings Zephyr had”
“10 years on a project then a full rewrite to zephyr - thats the move”
“the communication features of Zephyr RTOS are very important”
“Hopefully Zephyr helps unify the open source RTOS world in the same way Linux did for larger systems.”
“tries to be Posix-like in its APIs (but ends up not really improving things over the other embedded OSes TBH)”
“from my short three day experience with Zephyr I like uCLinux a lot better”
“Come over to Zephyr and see all the stuff you can run on boards from basically everyone”
“Zephyr's HAL streamlines the latter. Very nice.”
“the flash chip power management issue was quite bad”
“these are over-complicated overkill for MCUs”
“every major embedded SOC/MCU maker supports it”
“Their HAL works, their stacks work, the portability is incredibly smooth compared to other vendors.”
“an extremely capable RTOS with a decent shell, good features, and one of the best RTOS networking stacks out there”
“Kconfig silently disabling options because of missing dependencies sucks.”
“Zephyr is a baby project.”
“Zephyr blows away Arduino, it has portable stacks, security, update, wifi/ble, etc...”
“Great to see this is possible.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.