Dolos vs GPTZero

Dolos is a free, open-source tool for finding similarities between source-code submissions, particularly for teachers reviewing tests, exams, and exercises where collaboration may be allowed in small groups. Its analysis process tokenizes files, fingerprints token sequences, indexes matches, and produces reports. For each file pair, reports include similarity, total overlap, and the longest matching fragment. Dolos uses Tree-sitter parsers and supports languages including Bash, C, C++, C#, Elm, JavaScript, Java, PHP, Python, and TypeScript. The web app accepts ZIP files and detects languages from file extensions; in mixed-language archives, it analyzes only the dominant language unless a language is selected. Its public API accepts ZIP submissions up to 10 MB, with the CLI or library recommended for larger submissions. Analyses can also run locally, with results displayed in a browser, or on a self-hosted server. The free web app is hosted on Ghent University servers in Belgium. Dolos provides a JSON API for integrations such as Dodona and lists CSV as a report export format.

GPTZero identifies likely AI-generated writing and highlights detected AI use at document, sentence, and word level. Its detector can classify text as human, AI, or mixed, and provides confidence scores, explanations, AI vocabulary, and sentence-by-sentence highlighting. Advanced Scan points to passages contributing most to an AI classification. Users can submit pasted text or DOCX, PDF, and image files; the technology page says it can analyze up to 50 files at a time. GPTZero lists support for English, German, Portuguese, French, and Spanish, and detector coverage for text from ChatGPT, GPT-3 through GPT-6, Gemini, Claude, Copilot, and other models. Additional tools include Writing Replay, plagiarism checking, writing feedback, and grammar checking. The Chrome extension scans webpages and Google Docs, and integrations include Google Classroom, Canvas, an API, and Zapier. GPTZero says its results may be wrong, perform better on longer English prose, and should not be used alone to punish students. The free plan costs nothing. Paid plans start at $8.33 a month when billed annually.