# CodeIntelligenceTesting/jazzer

Coverage-guided, in-process fuzzing for the JVM

Repository: https://github.com/CodeIntelligenceTesting/jazzer
Canonical: https://ross.abutalabs.com/products/jazzer
Homepage: https://code-intelligence.com
Language: Java
License: Apache-2.0
License Family: permissive
Topics: fuzzing, java, fuzzer, jvm, security, kotlin, clojure, jni
Last push: 2026-09-02T21:31:46+00:00

## Health v2 (maintenance only)
Score: 86/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 60, longevity 100
- inputs: {"age_days": 2043, "days_push": 0, "days_rel": 190, "gap_med": 33.0, "n_releases_24m": 9}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1254, forks 170 (observed 2026-09-03T02:15:05.330405+00:00)

## What it is
Jazzer is a coverage-guided, in-process fuzz testing engine for the JVM, based on libFuzzer. It integrates with JUnit 5 and build tools like Maven, Gradle, and Bazel to find bugs and security vulnerabilities in Java, Kotlin, and Clojure code.

## Use cases
- fuzz test java code for security vulnerabilities
- find crashes and bugs in jvm applications with random inputs
- integrate fuzz testing into junit test suite
- coverage-guided fuzzing for kotlin or clojure
- detect vulnerabilities in java libraries before release
- run fuzz tests in ci with maven or gradle

## When to choose
- you develop JVM software (Java, Kotlin, Clojure) and want automated bug and vulnerability discovery
- you want fuzz tests to live alongside regular JUnit unit tests
- you need libFuzzer-style coverage-guided mutation on the JVM

## When to avoid
- your code does not run on the JVM (use libFuzzer, AFL++, or Jazzer.js instead)
- you only need conventional example-based unit tests without random input generation
- you need fuzzing for memory-unsafe native code with direct memory instrumentation

## Facets
- artifact type: library
- maturity: active
- function: fuzzing, testing, security, vulnerability-scanning
- domain: testing, security, developer-tools
- platform: windows, jvm, cli
- tags: java, kotlin, clojure, junit, libfuzzer, coverage-guided, maven, gradle, bazel, jvm, linux, macos

## Member repositories
- CodeIntelligenceTesting/jazzer (main) score 86

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:05.330405+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 2026-08-30T05:07:22.497607+00:00, confidence not recorded.
  - readme: https://github.com/CodeIntelligenceTesting/jazzer (fetched 2026-09-03T02:15:05.330405+00:00, sha e2a7a0b4a21b)
  - homepage: https://code-intelligence.com (fetched 2026-08-29T12:17:51.253520+00:00, sha 643ff698d465)
  - site_page: https://www.code-intelligence.com/about-us (fetched 2026-08-29T12:17:51.264949+00:00, sha f0e29412cdb5)
  - site_page: https://www.code-intelligence.com/product-ci-fuzz (fetched 2026-08-29T12:17:51.266624+00:00, sha e27e1dad42f6)
- Data as of 2026-08-30T08:39:29.467469+00:00.