Dolos review
A free, developer-focused checker for source-code similarity, with web, API, CLI, and self-hosting.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Dolos is an open-source source-code plagiarism detection tool developed by Team Dodona at Ghent University. It is designed primarily for teachers, programming courses, and developers who need to compare programming exercises. Users can upload ZIP files through the web application, while automatic programming-language detection supports analysis across multiple languages through Tree-sitter parsers. The core output is a similarity report with interactive visualizations, making Dolos a focused fit for programming assignments rather than general written content.
Its strongest advantage is the range of ways to fit source-code checking into a workflow. The web application supports ZIP-file submissions and interactive reports, while the JSON API supports automated submissions and CSV exports provide report data. Developers can also work offline through the command-line interface, integrate the JavaScript library, or run Dolos themselves with Docker Compose. Metadata support for submissions adds useful structure for course and assignment workflows, and Dodona integration connects it with that platform.
Dolos is free and open source, with no paid tier structure to weigh between feature levels. That makes it well suited to teams that want control over deployment, offline analysis, or integration details. Its limits are equally clear: URL checking is not part of its scope, and the product is built around source-code similarity rather than ordinary text, web pages, or scholarly publications. Choose Dolos for programming-course workflows and developer-led automation; choose a different category of checker for essays, webpages, or broader publication screening.
Dolos pros and cons
- Where it wins
- Free and open-source with web, API, CLI, and self-hosting options
- Interactive similarity visualizations with configurable thresholds
- JSON, CSV, Docker Compose, JavaScript, and Dodona integration
- Where it doesn't
- Focused on source code, not ordinary text, web pages, or scholarly publications
- Requires programming-language submissions packaged as ZIP files for web analysis
- Its breadth is narrower than general-purpose plagiarism checkers
Dolos fact sheet, pricing and score →
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