install

Additional install commands

macOS

Homebrewverified · 100%

brew install pyrefly

local Homebrew formula metadata

Linux

Nixverified · 92%

nix profile install nixpkgs#pyrefly

nixpkgs package indexes · pkgs/by-name/py/pyrefly/package.nix · source: api.github.com

Windows

Scoopverified · 92%

scoop install main/pyrefly

Scoop official bucket manifest trees · bucket/pyrefly.json · source: api.github.com

Windows Package Managerverified · 92%

winget install --id facebook.pyrefly -e

Windows Package Manager source index · facebook.pyrefly · source: cdn.winget.microsoft.com

overview

Package summary

Fast type checker and IDE for Python

Project links

Commands and aliases

pyrefly

From the blog

Pyrefly 1.0: A Type Checker Meets the Real Project
2026-10-22

history

Project history and usage

Pyrefly is Meta's high-performance static type checker and language server for Python, implemented in Rust for command-line and IDE workflows.

Project history

Meta announced Pyrefly publicly as an open-source alpha in May 2025 after developing a new checker around performance, IDE-first behavior, and extensibility. A beta followed in November 2025, and the project declared its stable 1.0 release in May 2026.

Adoption history

Meta developed Pyrefly for large Python codebases and made it the default type checker for Instagram's Python codebase. Official project materials also report adoption by large open-source projects including PyTorch and JAX.

How it is used

Users run `pyrefly init` to create or update project configuration and `pyrefly check` locally or in CI. The same analysis engine supports editor diagnostics and language features; migration commands can translate nearby mypy or Pyright settings.

Why package nerds care

Pyrefly is part of a newer generation of high-performance Python type checkers implemented in Rust. It combines a CLI checker and language server, supports migration from mypy and Pyright configurations, and is packaged across Homebrew, Nix, Scoop, and WinGet.

Timeline

2025: Meta announced Pyrefly as an open-source alpha.
2025: Pyrefly entered beta in November.
2026: Pyrefly reached its stable 1.0 milestone in May.

Related projects

mypy and Pyright are established Python type checkers with documented Pyrefly comparison and migration paths.
The Python typing specification defines the gradual-typing behavior these tools implement.
Pyrefly's language server supplies IDE navigation, completion, diagnostics, and refactoring features.

Sources

security posture

No protected-tool coverage found yet

No matching local secret-handling manifest was found for pyrefly. Package metadata is still published here so future coverage has a stable package URL.

Install behavior

No Homebrew post-install hook is recorded in formula metadata.
Homebrew bottle metadata is available for 5 platform targets.
Build metadata lists 1 build dependencies.

Recommended review

Before unattended agent use, check whether the tool reads plaintext credentials, writes remote state, publishes artifacts, or shells out to plugins.

local files

Configuration and credential file locations

These source-backed paths show where this package keeps local settings or durable credentials. Automic Vault can use them as review targets for secret scanning, migration, and command approval.

Configuration files

Config paths the tool may read or write during local use.

Unix: pyrefly.tomlpyproject.toml

executables

Installed executables

Command	Kind	Exposure	Note
`pyrefly`	cli	global executable

freshness

Version and freshness

These signals separate page generation age, package-manager activity, and upstream release comparison. Version lag is warned only when an evidence URL and comparable versions are present.

page generated2026-11-04

manager version1.4.0

manager updated2026-10-15

local dataok

upstreamcurrent

latest detected1.4.0

https://github.com/facebook/pyrefly

okNo freshness warnings were generated.

install metadata

Package metadata

Package key	brew:pyrefly
Version	1.4.0
Package manager	Homebrew
Package manager page	https://formulae.brew.sh/formula/pyrefly
Homepage	https://pyrefly.org/
Repository	https://github.com/facebook/pyrefly
Upstream docs	https://pyrefly.org/
License	MIT
Source archive	https://github.com/facebook/pyrefly/archive/refs/tags/1.4.0.tar.gz
Last updated	2026-10-15T18:41:02Z
Pulse	updated
Build dependencies	rust
Bottle	available (on arm64_golden_gate, arm64_linux, arm64_sequoia, arm64_tahoe, x86_64_linux)
Homebrew post-install	not defined
Service	none declared

registry facts

Source database details

Source Database	Homebrew formula API
Tap	homebrew/core
Full Name	pyrefly
Version Scheme	0
Revision	0
Head Version	HEAD
Bottle Stable Root URL	https://ghcr.io/v2/homebrew/core
Deprecated	no
Disabled	no
Keg Only	no
URL Keys	head stable

source database matches

Other package-manager records

Matches are pulled from external package-manager indexes and kept separate from local Automic Vault package links.

Nix95%

pyrefly

nix profile install nixpkgs#pyrefly

normalized package name match
Matched by: Pyrefly

nixpkgs package indexes · api.github.com · nixpkgs package indexes: pkgs/by-name/py/pyrefly/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1

Scoop95%

main/pyrefly

scoop install main/pyrefly

normalized package name match
Matched by: Pyrefly

Scoop official bucket manifest trees · api.github.com · Scoop official bucket manifest trees: bucket/pyrefly.json from https://api.github.com/repos/ScoopInstaller/Main/git/trees/master?recursive=1

winget95%

facebook.pyrefly

winget install --id facebook.pyrefly -e

normalized package name match
Matched by: Pyrefly

Windows Package Manager source index · cdn.winget.microsoft.com · Windows Package Manager source index: facebook.pyrefly from https://cdn.winget.microsoft.com/cache/source.msix

package graph

Links come from deterministic package relationships, av.db category and tag curation, ecosystem matches, and package hub membership.

source trail

Generated from repository data

This page is generated by av-web from the private package SQLite artifact built by scripts/generate-pkg-sqlite.py.

Combined YAML source

View the package source record on GitHub.

combined/pyrefly.yml

Used sources

Geiger risk classifier
cross-ecosystem install command graph
curated configuration and credential file locations
curated package history
external package-manager database matches
package relationship graph
package version freshness
package-page enrichment
pkg.so package database
pkgdb category and tag curation

Install pyrefly with Homebrew, Nix, scoop, winget