Duplo vs jscpd

Duplo is a free tool for locating duplicated source-code blocks in large codebases. It has built-in language support for C/C++, Java, C#, VB, GCC assembly, Ada, Erlang, TypeScript and Swift, and can also scan arbitrary text files, including for duplicates within one file. For supported languages, it can filter comments, preprocessor directives and other syntax before checking for repeated code. Files can be provided through standard input or a separate file list. Duplo produces text reports as well as JSON and XML output. The project describes XML reports as usable in continuous integration tools such as GitHub Actions and TeamCity, and links to a GitHub Actions extension that can fail a build when duplicates are found. That extension has settings for minimum duplicate lines, minimum line length and maximum files reported. Prebuilt binaries are available for Alpine Linux, macOS and Windows; it can also be built from source. Duplo is free under GNU GPL version 2 or later, and is provided without warranty.

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.