JPlag vs Plagius

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.

Plagius Desktop analyzes academic papers and other documents for possible plagiarism, checking the internet or local files. It supports Word, PDF, OpenOffice, PPT, HTML, RTF, and plain-text formats. Reports can identify suspicious phrases and sources, display URLs with similarity percentages, estimate suspected-plagiarism percentages, and show analysis-quality indicators; results can be opened in a browser or exported as HTML. Its V5 AI detector analyzes paragraphs in context and returns an AI-generation probability and confidence level. The site says it recognizes signals from more than 15 models, including Gemini 3.7, GPT 5.6, and Claude 5. Professional desktop plans add local and network-share searches, batch analysis, direct URL analysis, and file comparisons. The maker says desktop analysis is performed locally, but external searches may send text fragments, usually 7 to 13 words, to search engines. AI detection may send isolated paragraphs to Plagius servers, where excerpts are deleted within up to 48 hours. A free demo runs analysis but reveals only some results. Plagius One is browser-based and initially limited to invited users. Plagius Basic costs $6.90, paid once; its license lasts 30 days and is for one Windows computer. The maker cautions that automated results need manual review and cannot alone confirm plagiarism.