# seL4/seL4

The seL4 microkernel

Repository: https://github.com/seL4/seL4
Canonical: https://ross.abutalabs.com/products/sel4
Homepage: https://sel4.systems
Language: C
License: NOASSERTION
License Family: other
Topics: sel4-microkernel, os, microkernel, sel4
Last push: 2026-08-25T15:30:58+00:00

## Health v2 (maintenance only)
Score: 89/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 70, longevity 100
- inputs: {"age_days": 4429, "days_push": 8, "days_rel": 42, "gap_med": 111.0, "n_releases_24m": 3}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5717, forks 803 (observed 2026-08-28T04:09:28.220541+00:00)

## What it is
seL4 is a formally verified microkernel operating system kernel written in C, providing high-assurance isolation and capability-based security. It is designed for embedded and safety/security-critical systems and is typically used as a component within a larger build system.

## Use cases
- build a formally verified secure operating system kernel
- run isolated components on an embedded microkernel
- develop safety-critical or security-critical firmware
- learn about capability-based microkernel design
- port a microkernel to custom hardware
- achieve strong isolation between system components

## When to choose
- you need mathematically proven kernel correctness and strong isolation guarantees
- you are building embedded, automotive, avionics, or defense systems with high-assurance requirements
- you want a small, fast, capability-based microkernel foundation

## When to avoid
- you need a general-purpose desktop or server OS with broad driver support out of the box
- your team cannot handle the steep learning curve of capability-based microkernel programming
- you need a quick application platform rather than a kernel to build upon

## Facets
- artifact type: library
- maturity: active
- function: security, embedded
- domain: operating-systems, security, embedded-systems
- platform: embedded, iot, cross-platform, c
- tags: microkernel, formal-verification, kernel, capability-based-security, real-time, isolation, operating-systems

## Member repositories
- seL4/seL4 (main) score 89

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:28.220541+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:53:28.778481+00:00, confidence not recorded.
  - readme: https://github.com/seL4/seL4 (fetched 2026-08-28T04:09:28.220541+00:00, sha f104651c897f)
  - homepage: https://sel4.systems (fetched 2026-08-29T08:48:56.531056+00:00, sha e9cef41df2b9)
- Data as of 2026-08-30T08:39:29.467469+00:00.