Configuration¶

fuin reads configuration from environment variables, and from a .env file in the working directory. Copy .env.example to .env and set at minimum FUIN_API_KEY if you run the server.

Settings are read on every use, not captured at import time, so changing the environment takes effect without restarting a Python process.

Server¶

Only the server reads these. The packer ignores them.

Variable	Required	Default	Description
`FUIN_API_KEY`	yes	—	API key for every endpoint except `GET /`. The server refuses to start without it.
`FUIN_PACKED_DIR`	no	`./data/packed_apks`	Where packed APKs and mapping files are written
`FUIN_DATABASE_URL`	no	`sqlite:///./data/fuin.db`	SQLAlchemy database URL
`FUIN_MAX_UPLOAD_MB`	no	`500`	Largest accepted APK upload, in MB
`FUIN_MAX_MAPPING_MB`	no	`50`	Largest accepted ProGuard mapping upload, in MB
`FUIN_CLEANUP_DAYS`	no	`30`	Delete packed apps older than this many days at startup. `0` disables cleanup.
`FUIN_WEBHOOK_URL`	no	—	Comma-separated URLs to POST to when a pack job finishes

Signing¶

Shared by the CLI and the server pipeline. If the path or either password is missing, fuin generates a temporary debug keystore and logs a warning.

Variable	Default	Description
`FUIN_KEYSTORE_PATH`	debug keystore	PKCS12 keystore to sign with
`FUIN_KEYSTORE_ALIAS`	`fuin`	Key alias
`FUIN_KEYSTORE_STORE_PASS`	—	Keystore password
`FUIN_KEYSTORE_KEY_PASS`	—	Key password

Never ship a debug-signed build

Anti-tamper works by pinning the signing certificate. A debug keystore is generated fresh each run and its password is public, so an attacker can re-sign a modified APK and the check passes. Release builds must set FUIN_KEYSTORE_* or pass --keystore.

Packing defaults¶

These seed the packer's options. An explicit value from the CLI, the REST API or the Gradle plugin always wins; the environment only supplies the default when the caller says nothing.

Variable	Default	Description
`FUIN_ROOT_DETECTION`	`false`	Refuse to run on rooted devices
`FUIN_EMULATOR_DETECTION`	`false`	Refuse to run on emulators
`FUIN_ENCRYPT_STRINGS`	`false`	XOR-obfuscate DEX string constants
`FUIN_STRICT_MANIFEST_PATCH`	`true`	Fail the pack if `StubApplication` cannot be confirmed inserted
`FUIN_VERIFY_SIGNATURE`	`false`	Run `apksigner verify` after signing
`FUIN_STUB_DEX`	auto-detected	Path to a pre-built `stub.dex`, overriding the bundled one

Booleans accept 1, true or yes, case-insensitive. Anything else is false.

Integers must parse as integers — a malformed value raises a named error (FUIN_CLEANUP_DAYS must be an integer, got 'banana') rather than a bare traceback.

Precedence¶

For the tri-state packing options:

explicit argument  >  environment variable  >  built-in default

# environment supplies the default
FUIN_ROOT_DETECTION=true fuin-pack pack in.apk out.apk           # ON

# an explicit flag overrides it
FUIN_ROOT_DETECTION=true fuin-pack pack in.apk out.apk --root-detection   # ON

For keystore settings, an explicit --keystore overrides FUIN_KEYSTORE_PATH.

Docker¶

docker-compose.yml reads .env and mounts a named volume at /data. The image overrides two paths so state lands on the volume:

ENV FUIN_PACKED_DIR=/data/packed_apks
ENV FUIN_DATABASE_URL=sqlite:////data/fuin.db

Set anything else in .env:

.env

FUIN_API_KEY=change-me
FUIN_ROOT_DETECTION=true
FUIN_EMULATOR_DETECTION=true
FUIN_CLEANUP_DAYS=7

Database migrations¶

The server calls create_all() at startup, which is enough for a fresh install. Deployments that upgrade across versions should run Alembic instead:

alembic upgrade head

migrations/env.py reads FUIN_DATABASE_URL, so the same environment configures both.