CPAchecker vs Why3
CPAchecker
cpachecker.sosy-lab.orgWhy3
why3.orgSide by side
| Figure | CPAchecker | Why3 |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | — | Yes |
| Windows | Yes | Yes |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | — | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Formal Verification Tools | 8.0 (#10) | 8.0 (#12) |
| Development | Development takes place on GitLab, and the download page also links to a read-only GitHub mirror. | Why3 is developed by the Inria Toccata team, a joint research team of Inria Saclay-Île-de-France, Université Paris-Saclay, and CNRS. |
| Purpose | CPAchecker is a tool for configurable software verification based on configurable program analysis concepts. | Why3 is a platform for deductive program verification that uses WhyML and external theorem provers to discharge verification conditions. |
| Support | The project directs installation questions, bug reports, and suggestions to its CPAchecker users mailing list, and also provides an issue tracker. | The project provides a user mailing list, a Zulip chat, and a bug tracking system. |
Plans
In their own words
CPAchecker
CPAchecker is a configurable software verification tool based on configurable program analysis concepts. It accepts C and SV-LIB inputs, lists predicate analysis for SV-LIB programs, and supports invariants, counterexamples, and proof artifacts. It can also validate termination witnesses in YAML formats 2.1 and 1.0. The project lists a hybrid verification method and provides a self-hosted deployment. CPAchecker is free software under the Apache 2.0 License. Version 4.2.2, released in December 2025, is available as Unix and Windows ZIP archives; Debian and Ubuntu users can install it from the SoSy-Lab APT repository, and a Docker image is available. Java 21 or later is required as of version 4.2. An older version, 1.6.1, can be accessed through a web interface, where some functions are unavailable in the restricted environment. Documentation includes installation instructions, tutorials, and getting-started guidance. Installation questions, bug reports, and suggestions can go to the users mailing list or issue tracker. The project is based in Munich, Germany.
Why3
Why3 is a platform for deductive program verification. It uses WhyML to express programs and specifications, then works with external automated or interactive theorem provers to discharge verification conditions. WhyML supports preconditions, postconditions, assertions, and loop invariants, alongside logical theories and data structures such as arrays, queues, and hash tables. External provers need to be installed and configured separately. Why3 can be extended with support for new provers and used as a software library through its OCaml API. WhyML programs can be extracted automatically into correct-by-construction OCaml programs, and WhyML is also used as an intermediate language for verification of C, Java, Rust, and Ada. TryWhy3 provides a JavaScript version that runs in a browser. Installation options include Opam, Docker, source compilation, and listed Debian, Fedora, and Ubuntu packages. Its graphical interface saves proof attempts and transformations in an XML file and can replay obsolete attempts. Why3 is free and open source under GNU LGPL 2.1 with a special linking exception. Loop invariant inference is a work in progress, and many features remain very limited.