Side by side
Frama-C vs Why3
Both stand on formal verification tools. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan LinuxMacWindows
Frama-C offers several complementary analysis approaches for C, from runtime-error detection to contract-based proof and runtime checking. Its limitations around recursion, sequential analysis, and annotation translation matter when choosing which plug-ins fit a codebase.
Visit Frama-C Free plan APILinuxSelf-hosted+2
Why3 offers a verification workflow centered on WhyML, with extensibility and several installation routes. Account for the separate prover setup and the stated limits around loop invariant inference.
Visit Why3The facts
| Frama-C | Why3 | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Linux, Mac, Windows | API, Linux, Self-hosted, Web, Windows |
| Lowest paid plan | Not published | Free or on request |
| Plans published | None | 1 |
| Maker | Not published | Not published |
| Website | frama-c.com | why3.org |
| On formal verification tools | #21 of 34 | #25 of 34 |
Frama-C: what it does well
- Free and available for Linux, macOS, and Windows.
- Eva reports supported possible runtime errors.
- WP checks ACSL contracts across possible executions.
- Analyzers can combine results sequentially or in parallel.
- Plug-in development can extend or modify analyses.
What to know first
- Eva analyzes sequential code only.
- Eva does not support recursive calls.
- Some ACSL constructs cannot be translated by E-ACSL.
- Some specialized plug-ins are separate or proprietary.
Why3: what it does well
- Free and open source under GNU LGPL 2.1.
- Supports multiple external theorem provers.
- WhyML programs can be extracted to OCaml.
- Browser version available through TryWhy3.
- Proof attempts can be saved and replayed.
What to know first
- External theorem provers require separate installation and configuration.
- Loop invariant inference remains a work in progress.
- Many loop-invariant features are still very limited.