# google/nsjail

A lightweight process isolation tool that utilizes Linux namespaces, cgroups, rlimits and seccomp-bpf syscall filters, leveraging the Kafel BPF language for enhanced security.

Repository: https://github.com/google/nsjail
Canonical: https://ross.abutalabs.com/products/nsjail
Homepage: https://nsjail.dev
Language: C++
License: Apache-2.0
License Family: permissive
Topics: security, linux-namespaces, linux, process-isolation, seccomp-bpf-policies, chroot
Last push: 2026-08-26T19:39:10+00:00

## Health v2 (maintenance only)
Score: 91/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 75, longevity 100
- inputs: {"age_days": 4129, "days_push": 7, "days_rel": 168, "gap_med": 13, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4074, forks 359 (observed 2026-08-28T04:08:34.243334+00:00)

## What it is
NsJail is a lightweight Linux process isolation tool that uses namespaces, cgroups, rlimits, and seccomp-bpf syscall filters (via the Kafel BPF language) to sandbox untrusted processes. It supports inetd-style TCP listeners, one-shot execution, and repeated re-execution modes, making it useful for sandboxing network services and fuzzing targets.

## Use cases
- sandbox an untrusted binary with namespaces and seccomp filters
- run a network service in an inetd-style jail that forks per connection
- repeatedly execute a target process for fuzzing
- limit CPU, memory, and file descriptor usage of child processes
- isolate processes with chroot, pivot_root, and read-only bind mounts
- run commands as an unprivileged user inside a restricted environment

## When to choose
- you need fine-grained Linux sandboxing with namespaces, cgroups, and seccomp-bpf in one tool
- you want to sandbox network services or fuzzing targets on Linux
- you need resource limits and filesystem isolation for untrusted code

## When to avoid
- you need cross-platform sandboxing on macOS or Windows
- you prefer container-based isolation with full images and orchestration (use Docker instead)
- your kernel lacks support for user namespaces or seccomp-bpf

## Facets
- artifact type: cli-tool
- maturity: stable
- function: security, cli, developer-tools
- domain: security, developer-tools
- platform: cli
- tags: sandboxing, process-isolation, namespaces, seccomp, cgroups, chroot, fuzzing-support, command-line, linux

## Member repositories
- google/nsjail (main) score 91

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:34.243334+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 2026-08-29T18:23:28.960190+00:00, confidence not recorded.
  - readme: https://github.com/google/nsjail (fetched 2026-08-28T04:08:34.243334+00:00, sha fd1f0b958bda)
  - homepage: https://nsjail.dev (fetched 2026-08-29T09:15:26.121007+00:00, sha 1eba754c674c)
- Data as of 2026-08-30T08:39:29.467469+00:00.