copydetect vs jscpd

copydetect is a free tool for comparing code directories and producing an HTML report that highlights matching code slices. It uses Winnowing document fingerprinting, an approach also used by MOSS, and Pygments tokenization for the 500-plus languages Pygments can detect and tokenize. Users can compare test directories with reference directories such as previous submissions, and exclude boilerplate directories from matches. Noise, guarantee and display thresholds adjust what is detected and shown in reports. Install the package with pip; it requires Python 3.7 or later. The command-line tool recursively searches supplied directories, while its Python API supports comparisons and HTML report generation. Reports can be saved to a specified path, highlighted code can be truncated, and custom CSS can be linked. Configuration is available through command-line arguments or a JSON file. The package is MIT-licensed and classified for Education with Beta development status. Its documentation cautions that it may not catch plagiarism designed to evade detection and that a match does not establish that plagiarism occurred.

jscpd is a free, open-source tool for finding repeated code in repositories. It can fail a build when duplication exceeds a configured threshold, making it usable in local development and CI. The project says it supports 224 languages. Exact clones are detected by default, while renamed, near-miss, and semantic clone checks are optional; semantic detection is experimental.

Version 5 is available as a self-contained native binary that does not need Node.js, with direct macOS, Linux, and Windows binaries for x64 and ARM64. Reports include HTML, JSON, XML, README badges, SARIF, CodeClimate, and OpenMetrics. The GitHub Action can enforce a threshold and upload SARIF for GitHub Code Scanning, and GitLab CI reporters are documented. Developers can also use pre-commit hooks or Docker. A dashboard summarizes project size, duplication, complexity, dead code, and a health score. Dead-code analysis covers JavaScript, TypeScript, and Python, plus Rust when compiler diagnostics are supplied.