Skip to main content


Pyre can be run without a configuration (see Command Line Arguments) but we do recommend that you create a configuration (see Getting Started) and commit that to your version control system to make sure everyone working on your project is using the same settings.

Configuration Files#

Pyre has two types of configurations: a global configuration covering the full project, and local configurations that apply to subdirectories of the project. In most cases you will only need a global configuration but local configurations can be useful if you are dealing with a big repository containing heterogeneous projects.

The Global Configuration#

The global configuration is a .pyre_configuration file sitting at the root of your project. Running Pyre anywhere inside your project directory will use the settings in this global configuration. You can generate an initial configuration in your project directory with

$ pyre init

The configuration is a JSON file. For example,

"source_directories": [
"search_path": [

specifies that the code Pyre checks is in the directory of the configuration and that Pyre should look in an additional directory for library code.

You specify additional information to configure Pyre. The following fields are supported:

  • source_directories: List of paths to type check.

    Note: Pyre assumes that all imports are relative to the given source directory. For example, if your source directory is root/directory, then an import statement import module will be looking to import If you wish to set a different import root for your source directory, you can provide an object {"import_root": "root", "source": "directory"} instead of "root/directory". In this case, import module will be looking to import root.module.

  • search_path: List of paths to Python modules to include in the typing environment. Note: search_path takes precendence over source_directories and the order within the search path indicates precedence.

  • exclude: List of regular expressions such as ".*\/node_modules\/.*" which specify files and directories that should be completely ignored by Pyre. The regular expression will be matched against the full path of files as opposed to their relative path.

  • ignore_all_errors: A list of paths to omit from type-checking. This may be useful for generated files, virtualenv directories, etc. These should be paths relative to the location of the configuration file (or the local configuration if applicable) and support globs. Note: Files matching these paths will still be processed (i.e. type and module names in those files are still visible to Pyre). Please refer to the exclude configuration item if you have files that are intended to be hidden from Pyre.

  • binary: Location of Pyre's native binary.

  • logger: Pyre will invoke this exectuable on every run, passing it statistics in JSON format.

  • typeshed: Path to the Typeshed standard library, which provides typed stubs for library functions.

  • workers: Number of workers to spawn for multiprocessing.

  • extensions: Consider extensions in this list equivalent to .py for type checking. Empty string indicates extensionless files.

  • strict: Setting this to true will make strict mode the default in your project.

Local Configurations#

If you have sub-projects within your project root that you would like to run Pyre on, you can create a .pyre_configuration.local at the root of your subproject and override any of the fields set in .pyre_configuration above. If you are using local configurations, your .pyre_configuration should not specify any sources itself.

When calling Pyre, the nearest local configuration at- or above the current directory will be used. You can use the --local-configuration (or -l) flag to invoke Pyre on a project that includes a local configuration, while outside its source directory. It works like make -C:

$ ls project
.pyre_configuration.local ...
$ pyre -l project

Nested Local Configurations#

Nesting local configurations is not supported. The configuration should live at the root of your project unit and inclusion/exclusion of files from type checking can be done by specifying sources, using ignore_all_errors, or by adding local suppression.

Command Line Arguments#

You can get a full and current list of options to run Pyre by running pyre --help. The following is a list of commonly used commands and options.


Pyre comes with a couple commands that can be invoked with pyre <COMMAND>.

The first command you might come in contact with is

  • initialize, init: Initial setup of a configuration for a project.

If Watchman is installed, running Pyre with no positional arguments defaults to incremental, otherwise defaults to check.

  • check: Run Pyre end-to-end, i.e. not incrementally.
  • incremental: Run Pyre incrementally. When invoked for the first time, the command will automatically start a server listening to changes to the filesystem. Subsequent invocations will be faster.

When Pyre is run incrementally, you can control the Pyre's server working in the background with the following commands.

  • start: Start the Pyre server.
  • stop: Stop the Pyre server.
  • restart: Restart the Pyre server.
  • servers: List all currently running Pyre servers.
  • kill: In case somethign goes wrong and the server becomes unresponsivbe kill will attempt to terminate any processes.
  • rage: Print server logs for debugging or for context when reporting server errors.

Commonly Used Flags#

These flags can be passed in before any of the positional arguments above. For example:

$ pyre --source-directory "." --noninteractive check
$ pyre --source-directory "." restart
  • --local-configuration LOCAL_CONFIGURATION: Call Pyre specifying the path to a local configuration.

  • --noninteractive: Disable interactive logging, which by default overwrites intermediate logging output and adds colors for a more streamlined user experience. Non-interactive mode ensures all terminal output remains visible.

  • --output {text, json}: Formatting for error return values. Defaults to text.

  • --search-path SEARCH_PATH: Provide additional stubs or modules external to the project being type-checked. Can also be set in .pyre_configuration.

  • --source-directory SOURCE_DIRECTORY: Provide a path to the source root to check. This can also be specified in .pyre_configuration.

  • --typeshed TYPESHED: Path to the Typeshed standard library, which provides typed stubs for library functions. This can also be set in .pyre_configuration.

  • --verbose: Enable verbose logging. Most useful when used in conjunction with --noninteractive.

  • --version: Print the current version of Pyre.