Duplo
Duplo: A focused, free CLI scanner for finding duplicated source blocks across repositories. Ranked #10 of 23 in Code Clone Detection Tools by our editors (8.2/10); pricing: Free plan; best for simple cross-platform source-block scanning.
At a glance
- Editor score8.2 / 10
- PricingFree plan
- Best forSimple cross-platform source-block scanning
- Free planYes
- Paid fromFree
- Clone detection methodText
- Facts checked20 Sep 2026
Where it wins
- Filters comments and compiler directives by language.
- Exports scan results as JSON or XML with stylesheet support.
- Runs on Windows, macOS, and Linux with multithreaded scanning.
Where it doesn't
- Its documented workflow is command-line based rather than visual.
- Text-based matching provides less detection depth than higher-ranked tools.
- Automation centers on GitHub Actions rather than a broad integration set.
Our verdict on Duplo
Duplo is an open-source command-line tool for detecting duplicated code blocks across source files and large codebases. It suits developers and teams that want a free, self-hosted scanner for repository-wide checks without adopting a paid service. Duplo can analyze source files in several programming languages, apply language-aware filtering to comments and compiler directives, and examine arbitrary text files. Its cross-platform availability makes it practical for Windows, macOS, and Linux environments.
The tool fits automation-oriented workflows through file lists, standard-input filename streams, configurable minimum duplicate sizes, and multithreaded scanning. Results can be exported as JSON or XML, with stylesheet support for XML output. A separate GitHub Action supports automated repository scans, giving teams a direct path to include duplicate-block checks in GitHub Actions workflows. These options make Duplo more adaptable than a single interactive scan command, particularly when results need to move into scripts or reporting processes.
Duplo is intentionally focused on source-text comparison rather than a deeper analysis experience. Its text-based clone method can identify duplicate source blocks after language-specific filtering, but its detection depth is less detailed than higher-ranked tools. The command-line emphasis may also be a weaker fit for teams that expect a visual interface or broader platform integrations. Choose Duplo when free, open-source, self-hosted scanning and straightforward automation are the priorities; choose another tool when richer detection detail or a wider ecosystem matters more.
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Duplo pricing
Duplo fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Clone detection method | Text |
| Scan scope | Repository |
| CI integration | Yes |
| IDE integration | Not verified |
| Self-hosted option | Yes |
| Supported languages | Not verified |
| Deployment | Self-hosted |
| Platforms | Windows, macOS, Linux |
| Support | Community, Docs |
| Built for | Solo, Small business, Mid-market (editorial estimate) |
| Integrations | 1 integrations: GitHub Actions See all → |
| Pricing | Free plan |
| Website | github.com |
| Facts checked | 20 Sep 2026 |
Duplo integrations
Duplo lists 1 integrations on its own site.
- GitHub Actions
Alternatives to Duplo
- jscpdA broad, self-hosted clone detector with strong CI, reporting, and history analysis.9.4
- art-duplA focused, self-hosted clone analyzer for Go teams building duplication checks into CI.9.2
- PMDA strong open-source choice for teams pairing clone detection with broad static analysis.9.0
Also Ranked In
Duplo is ranked in 2 of our directories.
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Featured on iTechGuides
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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