Basedpyright is an open-source fork of Pyright: a Python type checker and language server that adds stricter diagnostics, extra rules, baseline support and Pylance-inspired editor features. You can install it as a Python package with uv or pip, then use its command-line checker or connect its language server to a supported editor.
What is basedpyright?
Basedpyright is a fork of Pyright, not a separate Python language or runtime. It checks Python code for type-related issues and provides Language Server Protocol (LSP) features for editors. The project describes it as “a fork of pyright with various type checking improvements, pylance features and more.” See the Basedpyright documentation for its feature and configuration details.
It is aimed at developers who want static type checking and editor assistance, including those who prefer not to rely on Microsoft’s closed-source Pylance extension.
Basedpyright vs. Pyright and Pylance
Pyright is the upstream type checker; Pylance is Microsoft’s VS Code language-server extension, built on Pyright. Basedpyright forks Pyright and develops additional checks and language-server functionality. The practical differences are in diagnostic strictness, feature availability, installation and how editor and command-line versions are managed.
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| Area | Basedpyright | Pyright | Pylance |
|---|---|---|---|
| Type checking | Stricter settings are enabled by default, and the project adds more than ten diagnostic rules. | Provides Pyright’s type checking; basedpyright’s additional rules and default strictness are its own changes. | Uses Pyright as its foundation and provides Microsoft’s language-server features. |
| Editor features | Reimplements Pylance-style features in its language server, with the aim of making them available in editors beyond VS Code. | Provides Pyright’s language-server functionality. | Microsoft’s language-server extension for VS Code; Microsoft recommends it for most VS Code users. |
| Installation | Available as a Python package through PyPI, including uv and pip; this route does not require a separate Node.js installation. |
Microsoft’s standard command-line installation uses npm. A separate community-maintained Python package is also available. | Installed as a VS Code extension. |
| CLI and editor version | The VS Code extension uses the package version installed in the environment, helping keep editor diagnostics aligned with the CLI. | Not stated in the cited installation guidance. | Not stated in the cited installation guidance. |
| Gradual adoption | Supports baselines, so a project can adopt stricter checking without first fixing every existing diagnostic. | Basedpyright’s baseline support is an added feature; equivalent support is not established here. | Not stated in the cited installation guidance. |
These are project and installation distinctions, not a guarantee that every diagnostic or editor feature behaves identically across versions. For upstream installation context, see Microsoft’s Pyright installation documentation.
What does basedpyright’s stricter checking catch?
Basedpyright enables stricter checking by default to make more potential issues visible, and adds more than ten diagnostic rules beyond Pyright’s set. The documentation identifies these as additional checks, but the cited feature summary does not enumerate every rule or map each one to a specific bug category. Consult the official documentation for the full rule list and configuration before treating any one diagnostic as a complete safety check.
Stricter checking can surface diagnostics in code that Pyright did not flag under the same setup. For an existing project, a baseline can record pre-existing diagnostics so you can introduce the checker without having to resolve them all at once.
Install basedpyright
The project recommends installing its Python package for most users. Choose one of these commands for your project:
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitches- With uv:
uv add --dev basedpyright - With pip:
pip install basedpyright
After installation, the basedpyright checker and basedpyright-langserver commands are available. The Python-package route does not require installing Node.js separately. The documentation also lists conda, Homebrew, NixOS and npm as distribution routes; see the installation guide for details.
Use basedpyright in an editor
Basedpyright supports editor integration through its VS Code/VSCodium extension and Open VSX distribution. The extension can disable Pylance automatically. If you need a Pylance-only capability, the project documents a configuration that uses basedpyright diagnostics with Pylance’s language server. That arrangement separates the source of diagnostics from the language server providing editor features, so follow the project’s setup instructions rather than enabling two competing checkers without configuration. See the IDE integration documentation.
Because it exposes an LSP server, basedpyright can also be connected to editors that support language servers, including Neovim. Exact setup depends on the editor and its LSP configuration; the cited documentation establishes the server command and VS Code/VSCodium extension support, not a single universal Neovim setup.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Which one should you choose?
- Choose basedpyright if you want stricter defaults, its extra rules or baseline-based adoption, or want a Python-package installation without a separate Node.js dependency.
- Choose Pyright if you want Microsoft’s upstream checker and its documented npm command-line installation.
- Choose Pylance if you primarily use VS Code and want Microsoft’s extension; Microsoft recommends it for most VS Code users.
One dated release reference should not be mistaken for a current version number: the repository search identified basedpyright v1.39.6, based on Pyright 1.1.410, dated May 24, 2026. Check the project’s release information for the version available when you install it.
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