android-reverse-engineering-skill

Android Reverse Engineering & API Extraction — Claude Code skill

A Claude Code skill that decompiles Android APK/XAPK/JAR/AAR files and extracts the HTTP APIs used by the app — Retrofit endpoints, OkHttp calls, hardcoded URLs, authentication patterns — so you can document and reproduce them without the original source code.

What it does

• Decompiles APK, XAPK, JAR, and AAR files using jadx and Fernflower/Vineflower (single engine or side-by-side comparison)
• Extracts and documents APIs: Retrofit endpoints, OkHttp calls, hardcoded URLs, auth headers and tokens
• Traces call flows from Activities/Fragments through ViewModels and repositories down to HTTP calls
• Analyzes app structure: manifest, packages, architecture patterns
• Handles obfuscated code: strategies for navigating ProGuard/R8 output

Requirements

Required:

• Java JDK 17+
• jadx (CLI)

Optional (recommended):

• Vineflower or Fernflower — better output on complex Java code
• dex2jar — needed to use Fernflower on APK/DEX files

See plugins/android-reverse-engineering/skills/android-reverse-engineering/references/setup-guide.md for detailed installation instructions.

Installation

From GitHub (recommended)

Inside Claude Code, run:

/plugin marketplace add SimoneAvogadro/android-reverse-engineering-skill
/plugin install android-reverse-engineering@android-reverse-engineering-skill

The skill will be permanently available in all future sessions.

From a local clone

git clone https://github.com/SimoneAvogadro/android-reverse-engineering-skill.git

Then in Claude Code:

/plugin marketplace add /path/to/android-reverse-engineering-skill
/plugin install android-reverse-engineering@android-reverse-engineering-skill

Usage

Slash command

/decompile path/to/app.apk

This runs the full workflow: dependency check, decompilation, and initial structure analysis.

Natural language

The skill activates on phrases like:

• "Decompile this APK"
• "Reverse engineer this Android app"
• "Extract API endpoints from this app"
• "Follow the call flow from LoginActivity"
• "Analyze this AAR library"

Manual scripts

The scripts can also be used standalone:

# Check dependencies
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/check-deps.sh

# Install a missing dependency (auto-detects OS and package manager)
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/install-dep.sh jadx
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/install-dep.sh vineflower

# Decompile APK with jadx (default)
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/decompile.sh app.apk

# Decompile XAPK (auto-extracts and decompiles each APK inside)
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/decompile.sh app-bundle.xapk

# Decompile with Fernflower
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/decompile.sh --engine fernflower library.jar

# Run both engines and compare
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/decompile.sh --engine both --deobf app.apk

# Find API calls
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/find-api-calls.sh output/sources/
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/find-api-calls.sh output/sources/ --retrofit
bash plugins/android-reverse-engineering/skills/android-reverse-engineering/scripts/find-api-calls.sh output/sources/ --urls

Repository Structure

android-reverse-engineering-skill/
├── .claude-plugin/
│   └── marketplace.json                    # Marketplace catalog
├── plugins/
│   └── android-reverse-engineering/
│       ├── .claude-plugin/
│       │   └── plugin.json                 # Plugin manifest
│       ├── skills/
│       │   └── android-reverse-engineering/
│       │       ├── SKILL.md                # Core workflow (5 phases)
│       │       ├── references/
│       │       │   ├── setup-guide.md
│       │       │   ├── jadx-usage.md
│       │       │   ├── fernflower-usage.md
│       │       │   ├── api-extraction-patterns.md
│       │       │   └── call-flow-analysis.md
│       │       └── scripts/
│       │           ├── check-deps.sh
│       │           ├── install-dep.sh
│       │           ├── decompile.sh
│       │           └── find-api-calls.sh
│       └── commands/
│           └── decompile.md                # /decompile slash command
├── LICENSE
└── README.md

References