Deckard vs Duplo
Deckard
github.comDuplo
github.comSide by side
| Figure | Deckard | Duplo |
|---|---|---|
| Price from | — | Free |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | — |
| Plans published | 0 | 1 |
| Spec score · Code Duplication Detection Tools | 7.5 (#8) | 7.9 (#5) |
| Spec score · Code Clone Detection Tools | 7.5 (#12) | 7.9 (#5) |
| License | The repository license permits source and binary redistribution subject to its stated conditions and disclaims warranties. | Duplo is free software under the GNU General Public License version 2 or, at the user's option, any later version, and is provided without warranty. |
| Maintainer | The GitHub account associated with the repository identifies its user as Lingxiao Jiang and lists Singapore Management University and Singapore. | Duplo was originally developed by Christian M. Ammann and is now maintained and developed by Daniel Lidström. |
| Performance | Version 2.0 supports parallel execution, with the maximum process count set through the MAX_PROCS configuration value. | The README reports processing 266 Quake2 files and 102,740 lines in 9 seconds on modern hardware in 2025, and says multithreading offers almost linear improvement. |
| Purpose | Deckard is a tree-based code clone detection tool that can also report clone-related bugs. | Duplo finds duplicated code blocks in large codebases. |
| Reports | The tool can convert clone or bug reports into HTML for inspection in a browser. | Duplo can output results as JSON or XML, and its XML can be displayed in a browser using an included stylesheet. |
Plans
In their own words
Duplo
Duplo is a free tool for locating duplicated source-code blocks in large codebases. It has built-in language support for C/C++, Java, C#, VB, GCC assembly, Ada, Erlang, TypeScript and Swift, and can also scan arbitrary text files, including for duplicates within one file. For supported languages, it can filter comments, preprocessor directives and other syntax before checking for repeated code. Files can be provided through standard input or a separate file list. Duplo produces text reports as well as JSON and XML output. The project describes XML reports as usable in continuous integration tools such as GitHub Actions and TeamCity, and links to a GitHub Actions extension that can fail a build when duplicates are found. That extension has settings for minimum duplicate lines, minimum line length and maximum files reported. Prebuilt binaries are available for Alpine Linux, macOS and Windows; it can also be built from source. Duplo is free under GNU GPL version 2 or later, and is provided without warranty.