trix

trix - trick yourself into flakes

trix is an alternative userland implementation of Nix flakes. It reads flake.nix and flake.lock files, resolves inputs, and evaluates outputs — all without requiring you to enable the experimental flakes or nix-command features. Under the hood, trix delegates to the stable "legacy" Nix commands (nix-build, nix-shell, nix-instantiate), giving you a modern flake workflow built on proven foundations.

Why?

While flake.nix has reached critical mass and there is no going back at this point, this doesn't mean we are stuck with the current implementation of Flakes.

The primary motivation for trix is to address the stagnation of these "experimental" features. Despite being broadly adopted, flakes and nix-command have remained in experimental status for a significant time. This uncertainty creates a barrier to adoption (where using "experimental" features is often seen as a liability) and maintains ambiguity regarding their future. trix tries to bridges this gap, treating the Flake format as the standard while relying on the proven stability of traditional Nix internals.

trix allows using Nix as if the experimental feature flags nix-command and flakes were enabled, without modifying your global configuration. It works by delegating to stable "legacy" Nix commands (nix-build, nix-shell, nix-instantiate) whenever possible, rewriting each command to optionally inject --extra-experimental-features "flakes nix-command" when necessary.

This approach offers these benefits:

• No Global Configuration: You can keep your nix.conf clean of experimental-features = nix-command flakes.
• Efficiency: trix evaluates flakes in-place without copying them to the Nix store, referencing your working directory directly.
• Stability: It leverages the battle-tested legacy Nix tools under the hood.

Comparison

vs nix flake

Feature	nix flake	trix
Stability	Experimental	Stable (uses nix-build, etc.)
Purity	Enforced	Optional (allows impure evaluation)
Performance	Copies entire flake to store	Efficient (evaluates in-place, no store copy)
Specification	Full	Practical subset

vs plain nix-build / nix-shell

Feature	Plain Nix	trix
flake.nix support	❌	✅
Reproducible locking	Manual	✅ (native flake.lock)
Structured inputs	❌	✅
CLI familiarity	Legacy	Modern (flake-like)

How it Works

trix is a small rust tool, written initially in python by claude and converted to rust with Antigravity later on, that provides a flake-like experience using stable Nix commands. It operates as follows:

1. Introspection: Parses flake.nix to extract input requirements (via nix-instantiate).
2. Locking: Fetches and locks inputs using nix flake prefetch. (For remote flakes and certain operations like trix copy, trix delegates to nix commands directly.)
3. Generation: Produces a standard flake.lock file.
4. Evaluation: Constructs the inputs attrset and evaluates the flake's outputs.
5. Execution: Delegates the final build or shell action to nix-build or nix-shell.

The resulting lock file is fully compatible with using nix flake experimental features. You can even switch between trix and official Flakes at any time without issues.

trix translates high-level flake intents into low-level Nix operations. When running a trix command, it actually invokes multiple Nix commands under the hood to build the desired output. These commands includes the experimental features flags for you (some required functions requires flakes to be enabled, like NixOS/nix#5541).

Direnv Integration

trix includes a direnv library for seamless environment activation.

1. Add to your ~/.config/direnv/direnvrc:

   # If installed via nix profile:
   source ~/.nix-profile/share/trix/direnvrc
   # Or with a direct store path:
   source /nix/store/...-trix-0.1.0/share/trix/direnvrc

2. In your project's .envrc:

   use trix
   # or for a specific devShell:
   use trix .#myshell

Debugging

trix uses structured logging via the tracing crate. Diagnostic information is printed to stderr to avoid interfering with command output.

Verbose Mode

Use the -v / --verbose flag to enable debug output:

trix -v build .#default

Environment Variables

You can filter log output granularly using the RUST_LOG environment variable. The default level is INFO (or DEBUG when -v is used).

Examples:

# different modules at different levels
RUST_LOG=trix=debug,nix=error trix build

# trace everything
RUST_LOG=trace trix build

See Also

• Nix Flakes: The experimental feature trix provides an alternative for.
• flake-compat: Makes flake-based projects compatible with legacy Nix commands.
• unflake: An alternative dependency resolver & runtime for Nix flakes.