# jepsen-io/jepsen

A framework for distributed systems verification, with fault injection

Repository: https://github.com/jepsen-io/jepsen
Canonical: https://ross.abutalabs.com/products/jepsen
Language: Clojure
License Family: other
Last push: 2026-08-26T15:45:01+00:00

## Health v2 (maintenance only)
Score: 89/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 71, longevity 100
- inputs: {"age_days": 4889, "days_push": 7, "days_rel": 34, "gap_med": 97, "n_releases_24m": 8}
- 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 7481, forks 754 (observed 2026-08-28T04:10:00.211137+00:00)

## What it is
Jepsen is a Clojure library and framework for verifying the correctness of distributed systems under fault injection. It sets up systems on remote nodes, runs concurrent client operations, injects faults via a nemesis, and checks the resulting history for consistency violations.

## Use cases
- verify linearizability of a distributed database
- test how a system behaves under network partitions
- check consistency of a distributed task scheduler
- generate performance and availability graphs during faults
- inject clock skew and crash faults into a cluster
- validate eventual consistency guarantees

## When to choose
- you need rigorous correctness verification of a distributed system
- you want to reproduce and analyze consistency anomalies under faults
- you are building or auditing a database, queue, or coordination service

## When to avoid
- you need simple unit or integration tests without distributed fault injection
- you cannot provision SSH-accessible test nodes
- your team has no Clojure/JVM experience and only needs ad-hoc smoke tests

## Facets
- artifact type: framework
- maturity: active
- function: testing, e2e-testing, benchmarking, fuzzing
- domain: microservices, databases, testing, developer-tools
- platform: jvm-scripting, jvm, cli
- tags: distributed-systems-verification, fault-injection, consistency-checking, nemesis, chaos-engineering, linux

## Member repositories
- jepsen-io/jepsen (main) score 89

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:00.211137+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 2026-08-29T17:37:35.842907+00:00, confidence not recorded.
  - readme: https://github.com/jepsen-io/jepsen (fetched 2026-08-28T04:10:00.211137+00:00, sha 64e28dfc68c6)
- Data as of 2026-08-30T08:39:29.467469+00:00.