Feature flags

loco-rs gates most of its optional functionality behind Cargo features, declared in root Cargo.toml:27-64. This page is the exhaustive matrix — every flag, its default state, what it turns on, and how flags interact with each other and with cargo loco.

Defaults

default = ["auth", "cli", "with-db", "cache_inmem", "worker"]

A plain loco-rs = "..." dependency (no default-features = false) pulls in JWT auth, the cargo loco CLI, Sea-ORM database support, the in-memory cache, and the Postgres/SQLite-backed queue workers. The Redis-backed queue worker (worker_redis) is not in the default set — opt in explicitly if your app uses a Redis queue.

The matrix

Flag	Default	Enables (deps / sub-features)	Purpose
`auth`	ON	`dep:jsonwebtoken`, `jsonwebtoken/rust_crypto`	JWT authentication. Selects `jsonwebtoken`’s pure-Rust `rust_crypto` backend (jsonwebtoken 10 no longer bundles a crypto backend by default), so the flag stays self-contained and needs no C toolchain, even when enabled alone with `default-features = false`.
`cli`	ON	`dep:clap`	Enables the `cargo loco` runtime CLI (`src/cli.rs`).
`with-db`	ON	`dep:sea-orm`, `dep:sea-orm-migration`, `dep:sqlx`, `loco-gen/with-db`	Sea-ORM 2.0.0-rc database support. Gates the `db` CLI subcommand and the DB-dependent generators (`model`, `migration`, `scaffold`).
`testing`	off	`dep:axum-test`, `dep:scraper`, `dep:tree-fs`	Test harness utilities. Also the feature set built for docs.rs (`[package.metadata.docs.rs] features = ["testing"]`, `Cargo.toml:211-212`) and used by the crate’s own `dev-dependencies`.
`cache_inmem`	ON	`dep:moka`	In-memory cache backend.
`cache_redis`	off	`dep:bb8-redis`, `dep:bb8`	Redis-backed cache pool.
`worker`	ON	`dep:sqlx`, `dep:ulid`	Background job queue/workers, Postgres and SQLite backends. Which one runs is chosen at runtime by `queue.kind` in config (`Postgres` or `Sqlite`), not by a separate feature per database.
`worker_redis`	off	`worker`, `dep:redis`	Adds the Redis-backed queue backend on top of `worker` (implies it). Enable this if your app’s `queue.kind` is `Redis`.
`all_storage`	off	`storage_aws_s3` + `storage_azure` + `storage_gcp`	Umbrella flag — turns on every cloud storage backend at once.
`storage_aws_s3`	off	`opendal/services-s3`	AWS S3 storage backend.
`storage_azure`	off	`opendal/services-azblob`	Azure Blob storage backend.
`storage_gcp`	off	`opendal/services-gcs`	Google Cloud Storage backend.
`embedded_assets`	off	(empty — build-time flag)	Embeds the app’s `assets/` directory into the compiled binary and swaps the view-engine’s asset-loading path accordingly, instead of reading assets from disk at runtime.

Source: root Cargo.toml:27-64.

Interactions

worker unlocks the jobs subcommand. cargo loco jobs (and its cancel/tidy/purge/dump/import/requeue subcommands) is compiled whenever the worker feature is enabled (#[cfg(feature = "worker")], src/cli.rs:27). The same cfg gates the JobStatus import used by the jobs machinery. Since worker_redis implies worker, the jobs CLI is available for any queue backend — Redis, Postgres, or SQLite.
debug_assertions (not a Cargo feature) gates generate and db entities. The cargo loco generate subcommand and the db entities subcommand are compiled only in debug builds (#[cfg(debug_assertions)], src/cli.rs:29, 140, 173). They are unavailable in --release builds regardless of which Cargo features are on.
all_storage is a pure umbrella. It has no dependency of its own; it just turns on storage_aws_s3, storage_azure, and storage_gcp together.
auth selects jsonwebtoken/rust_crypto. Because jsonwebtoken 10 unbundled its crypto backend, auth explicitly enables the rust_crypto sub-feature so JWT support keeps working without requiring a system C toolchain (e.g. OpenSSL).
with-db is a prerequisite, not an implication. Enabling worker does not itself pull in with-db; the two are independent flags that happen to share the sqlx dependency.
The queue backend is chosen at runtime, not by feature flag. worker builds in the Postgres and SQLite queue providers; which one actually runs is decided by queue.kind (Postgres or Sqlite) in your app config. worker_redis adds the Redis provider, selected the same way with queue.kind: Redis. See Choose a queue backend.

Disabling defaults

To opt out of the default set (e.g. a DB-less app), depend with default-features = false and re-list only the flags you want:

loco-rs = { version = "...", default-features = false, features = ["cli"] }

This is the pattern the loco new generator itself uses when the app is created without a database (see the CLI reference’s app-creation flow): it emits default-features = false with features = ["cli"], plus worker_redis if a Redis-backed queue was selected, or worker if a Postgres- or SQLite-backed queue was selected.