# facebook/redex

A bytecode optimizer for Android apps

Repository: https://github.com/facebook/redex
Canonical: https://ross.abutalabs.com/products/redex
Homepage: https://fbredex.com/
Language: C++
License: MIT
License Family: permissive
Last push: 2026-08-26T23:03:40+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 87, longevity 100
- inputs: {"age_days": 3814, "days_push": 7, "days_rel": 89, "gap_med": 10, "n_releases_24m": 6}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6299, forks 681 (observed 2026-08-28T04:09:41.540260+00:00)

## What it is
ReDex is a C++ bytecode optimizer for Android dex files, originally developed at Facebook. It provides a framework for reading, writing, and analyzing .dex files plus configurable optimization passes that make APKs smaller and faster.

## Use cases
- reduce android apk size
- optimize dex bytecode for faster app startup
- shrink app download size for mobile users
- inline and remove unreachable code in android apps
- integrate bytecode optimization into buck android builds
- re-sign optimized apks with debug or release keys

## When to choose
- you build Android APKs and want smaller, faster bytecode
- you use Buck and want integrated dex optimization
- you need configurable, pass-based dex optimization with ProGuard map support

## When to avoid
- you only need resource or asset compression rather than bytecode optimization
- your app relies heavily on reflection without keep annotations, risking stripped classes
- you need a simple one-click build tool without C++ toolchain setup

## Facets
- artifact type: cli-tool
- maturity: active
- function: compiler, developer-tools, build-tool
- domain: mobile-development, developer-tools, performance
- platform: windows, cli
- tags: android, dex, bytecode-optimizer, apk-optimization, app-size-reduction, buck, linux, macos

## Member repositories
- facebook/redex (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:41.540260+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:46:16.089563+00:00, confidence not recorded.
  - readme: https://github.com/facebook/redex (fetched 2026-08-28T04:09:41.540260+00:00, sha c054b492ff7c)
  - homepage: https://fbredex.com/ (fetched 2026-08-29T08:42:51.418075+00:00, sha 6745383e3769)
  - site_page: https://fbredex.com/docs/getting_started/installation (fetched 2026-08-29T08:42:51.426937+00:00, sha e13eefa63e44)
  - site_page: https://fbredex.com/docs/getting_started/configuring (fetched 2026-08-29T08:42:51.429155+00:00, sha eacb084f9d04)
  - site_page: https://fbredex.com/docs/getting_started/usage (fetched 2026-08-29T08:42:51.430962+00:00, sha 34e0b0ea0156)
  - site_page: https://fbredex.com/docs/help/faq (fetched 2026-08-29T08:42:51.432597+00:00, sha 51358ed99805)
- Data as of 2026-08-30T08:39:29.467469+00:00.