jadx

name	jadx
description	Use jadx for authorized Android APK, DEX, AAR, and JAR decompilation, app logic review, API endpoint discovery, credential checks, and mobile reverse engineering.

jadx

Use jadx to decompile Android APK, DEX, AAR, and JAR inputs into readable Java source and decoded resources. Prefer CLI output that can be searched, scripted, and archived.

Help First

Before constructing commands, run the installed help and use it as the source of truth:

jadx --help

Usage Rules

• Work only on provided Android artifacts or explicitly authorized mobile applications.
• Prefer task-scoped output directories and preserve the original input file.
• Ensure the output directory is writable and has enough space because decompiled output can be several times larger than the input.
• Start from resources/AndroidManifest.xml, then inspect entry points and security-sensitive packages under sources/.
• Use --deobf for obfuscated apps and --show-bad-code when partial decompilation is useful.
• Use apktool when manifest, resources, smali, or packaging fidelity matters more than readable Java-like source.
• Save large grep results and decompiled snippets to files rather than streaming them into the conversation.

Common Workflows

# Standard decompilation
jadx app.apk -d app-jadx

# Recommended for obfuscated production apps
jadx --deobf app.apk -d app-jadx

# Faster code-only pass
jadx --no-res --deobf app.apk -d app-code

# Resources-only pass
jadx --no-src app.apk -d app-resources

# Preserve partially decompiled methods when errors occur
jadx --show-bad-code app.apk -d app-jadx

# Fallback mode for difficult inputs
jadx --fallback --show-bad-code app.apk -d app-jadx

Output Layout

app-jadx/
├── sources/                 # Decompiled Java source
│   └── com/example/app/
└── resources/               # Decoded Android resources
    ├── AndroidManifest.xml
    ├── res/
    └── assets/

Start analysis from resources/AndroidManifest.xml, then inspect entry points and security-sensitive packages under sources/.

Recommended Workflow

apk=app.apk
out=app-jadx

jadx --deobf --show-bad-code "$apk" -d "$out"

# Entry points and components
grep -r "extends Activity\|extends AppCompatActivity\|extends Application\|extends Service\|extends BroadcastReceiver" "$out/sources/"

# URLs and API declarations
grep -rE 'https?://[^"'"'"']+' "$out/sources/" "$out/resources/"
grep -r "@GET\|@POST\|@PUT\|@DELETE\|@PATCH\|baseUrl\|BASE_URL\|API_URL" "$out/sources/"

# Secrets and credentials
grep -ri "api.*key\|apikey\|secret\|password\|passwd\|token\|bearer" "$out/sources/" "$out/resources/"

# Crypto, storage, WebView, TLS handling
grep -r "Cipher.getInstance\|MessageDigest\|DES\|MD5\|SHA1\|SecureRandom" "$out/sources/"
grep -r "SharedPreferences\|SQLite\|openFileOutput\|MODE_WORLD_READABLE\|MODE_WORLD_WRITABLE" "$out/sources/"
grep -r "setJavaScriptEnabled.*true\|addJavascriptInterface\|WebView.*loadUrl" "$out/sources/"
grep -r "TrustManager\|HostnameVerifier\|CertificatePinner\|checkServerTrusted" "$out/sources/"

Common Analysis Tasks

API Endpoint Discovery

jadx --deobf app.apk -d app-jadx

find app-jadx/sources \
  -name '*Api*.java' -o \
  -name '*Service*.java' -o \
  -name '*Client*.java'

grep -r "@GET\|@POST\|@PUT\|@DELETE\|@PATCH" app-jadx/sources/ | sort -u
grep -r "baseUrl\|BASE_URL\|API_BASE\|API_URL" app-jadx/sources/ app-jadx/resources/ | sort -u

Credential Check

jadx --no-res --deobf app.apk -d app-code

grep -ri "api.*key\|apikey\|client.*secret\|secret.*key" app-code/sources/
grep -ri "username.*password\|user.*pass\|password\|passwd\|pwd" app-code/sources/
grep -ri "token\|jwt\|bearer\|authorization" app-code/sources/

IoT Companion App Review

jadx --deobf iot.apk -d iot-jadx

grep -rE 'https?://[^"'"'"']+' iot-jadx/sources/ iot-jadx/resources/ | grep -vi "google\|android\|facebook"
grep -ri "discover\|scan\|broadcast\|mdns\|udp\|mqtt\|coap\|onvif" iot-jadx/sources/
grep -ri "Authorization\|apiKey\|token\|login\|authenticate" iot-jadx/sources/
grep -r "CertificatePinner\|TrustManager\|HostnameVerifier" iot-jadx/sources/

Batch Processing

for apk in *.apk; do
  name=$(basename "$apk" .apk)
  out="jadx-$name"
  jadx --no-res --deobf "$apk" -d "$out"
  grep -ri "api.*key\|password\|secret\|token\|baseUrl" "$out/sources/" > "findings-$name.txt" || true
done

Useful Options

• --deobf: rename obfuscated classes and members where possible.
• --use-source-name-as-class-name-alias: use source file names as deobfuscation hints; valid values include always, if-better, and never.
• --show-bad-code: emit partial code for methods jadx cannot cleanly decompile.
• --fallback: use fallback decompilation when normal output fails.
• --no-res: skip resources for faster source-only analysis.
• --no-src: decode resources without Java source output.
• --export-gradle: export a Gradle project layout.
• -j <threads>: set decompilation thread count.

Troubleshooting

# Obfuscated names make code hard to follow
jadx --deobf --use-source-name-as-class-name-alias if-better app.apk -d app-jadx

# Decompiler errors hide important logic
jadx --show-bad-code --fallback app.apk -d app-jadx

# Large APK is slow
jadx --no-res -j 8 app.apk -d app-code

# Need build-like project structure
jadx --export-gradle app.apk -d app-project

Output

Report the APK or artifact path, hash if available, jadx command used, output directory, relevant paths under sources/ or resources/, exact constants/URLs/methods/components found, why the finding matters, and limitations such as decompiler errors or obfuscation.