JPlag vs PlagiarismSearch

JPlag is free, open-source software for finding pairwise similarities among submitted programs. It examines program syntax and structure to help detect source-code plagiarism and collusion, especially in student programming exercises, and can also identify duplicated or stolen software parts. It does not compare submissions with the internet. Supported inputs include Java, C, C++, C#, Python, JavaScript, TypeScript, Go, Kotlin, R, Rust, Swift, Scala, LLVM IR, Scheme, EMF, SCXML, text, and multi-language projects. JPlag runs locally, with the project stating that source code and plagiarism results are not sent externally. You can use its command-line interface, Java API, or Maven Central dependency. A bundled report viewer opens generated or existing reports. Base-code directories can exclude shared starter code, while matching-token sensitivity is adjustable. The default report lists up to 2500 comparison pairs, configurable with -n. Running or building it requires Java SE 25.

PlagiarismSearch checks submitted writing against selected web, archived, publication, academic, and enabled organizational sources. Its reports identify matching or similar passages, link those passages to detected sources, and provide a similarity report. An AI writing feature gives probability indicators for the full text and individual passages, highlighting passages for review. The service also lists paper analysis, readability, and spelling and grammar tools. Users can check up to 150 words for free, while registered users can check up to 300 words daily at no charge. The maker says its academic database contains over 500 million indexed texts. Integrations include a Moodle plugin, Google Docs add-on, customizable API, and Viber and Telegram bots. The maker presents it for students, educators, writers, bloggers, universities, and organizations. Paid options include a Light one-time package at $9.95, paid once and monthly packages from $27.95 a month. The maker says uploaded documents are not stored, though reports may remain in an account until deleted by the user.