ast-grep vs Understand
ast-grep
ast-grep.github.io
Understand
scitools.comSide by side
| Figure | ast-grep | Understand |
|---|---|---|
| Price from | Free | $100/mo |
| Free plan | Yes | — |
| Free trial | — | Yes |
| Open source | — | — |
| Web | Yes | — |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | — | Yes |
| Plans published | 1 | 2 |
| Spec score · Code Search Tools | 9.1 (#1) | 8.5 (#2) |
| Languages | The project says it supports 20+ languages and allows custom languages to be loaded. | Supported language families include Ada, assembly, C/C++, C#, Fortran, Java, JOVIAL, Pascal/Delphi, Python, VHDL, Visual Basic and web languages. |
| Language support | The site says ast-grep supports 20+ programming languages and can load custom languages. | Supported languages include C/C++, C#, Fortran, Java, Python, Rust, VHDL, Visual Basic, and web languages including HTML, CSS, JavaScript, TypeScript, PHP, and XML. |
| Support | The project directs users with questions or issues to GitHub or Discord and also points to Stack Overflow and Reddit. | SciTools provides product support by email and lists office hours Monday through Friday, 9 AM–5 PM Mountain Time. |
| What it does | ast-grep is a fast, polyglot tool for structural code search, linting, and large-scale rewriting. | Understand is a desktop source-code comprehension and static-analysis environment that builds navigable models of code relationships, metrics and standards findings. |
Plans
Understand
- Understand subscription$100 a month
- Understand annual subscriptionPrice not published
In their own words
ast-grep
ast-grep is a free, open-source tool for structural code search, linting, and rewriting. It matches patterns against syntax-tree nodes, helping developers locate and change code across a codebase rather than searching plain text. Its CLI can preview and apply rewrites interactively, and scan configurable YAML rules with error, warning, info, or hint severity. Rules can combine pattern, kind, regex, relational, and composite conditions, and CLI commands help create and snapshot-test them. The project says it supports more than 20 languages and can load custom languages. JavaScript and WebAssembly APIs allow programmatic syntax-tree work; a browser playground offers a way to try patterns without local installation. Editor options include a VS Code extension and language-server setups, including for Vim and Neovim. The tool is free, has a web interface, and is distributed through package managers or built from source. Its FAQ notes that some advanced static-analysis information is unsupported, and one rule cannot target multiple languages at once.
Understand
Understand is a static analysis and code-comprehension tool from SciTools. It builds a cross-referenced model of source code without executing it, then helps users explore relationships through its Information Browser, call trees, dependency analysis, and visual graphs, including butterfly and control-flow views. It also provides metrics, CodeCheck, version comparison, APIs, a command-line interface, and AI chat. Supported languages include C/C++, C#, Fortran, Java, Python, Rust, VHDL, Visual Basic, and web languages such as HTML, CSS, JavaScript, TypeScript, PHP, and XML. It runs on Windows 11, specified Linux distributions, and macOS Monterey or later; command-line automation, CI, and an official Docker image are also available. The VS Code extension is separately licensed. Local AI keeps code and prompts on the user's hardware, while cloud AI sends requests with code context to the selected provider. Offline use is supported with offline licensing. Pricing includes a free plan and paid subscriptions from $100/user/mo (annual).