JPlag vs Originality.ai

JPlag is free software for finding pairwise similarities among programs that may indicate source-code plagiarism or collusion. It examines programming-language syntax and program structure, helping identify overlap even when code has been partly obfuscated. Analysis runs locally on the user’s machine, and the project says no data is sent externally. Comparisons are between submitted programs rather than internet sources. Listed language support includes Java, C, C++, C#, Python, JavaScript, TypeScript, Go, Kotlin, R, Rust, Swift, Scala, LLVM IR, Scheme, EMF, SCXML, text, and multi-language submissions, with varying maturity. Users can run the command-line interface or Java API, launch a report viewer from the CLI, or add JPlag through Maven Central. Reports show at most 2,500 pairs by default, adjustable with the -n option. Lower minimum matching-token lengths increase sensitivity but can also increase false positives. Running or building requires Java SE 25.

Originality.ai provides tools for checking AI-generated text, plagiarism, facts, readability, grammar, spelling and content quality. Its free Basic plan costs $0.00 per free and provides three AI scans per day, with up to 2,000 words per scan. The AI detector offers configurable allowances of 0%, 5%, 15%, 25% or 40%. A website scanner can crawl a site, identify pages likely to contain AI-generated content and run scheduled scans. The browser extension scans Google Docs, web pages or selected text, and includes writing replay, typing behavior insights and shareable reports. A REST-based API submits text for AI and plagiarism scans and returns detailed results; the maker says AI detection supports 30 languages. API AI scans require at least 50 words, and the help page says accuracy decreases below 100 words. Originality.ai describes detection results as probabilistic estimates that may produce false positives or false negatives, not conclusive proof. Pro costs $12.95 per month billed yearly, with a monthly option at $14.95 per month. The service is available through web, API and extension.