flkr

Detect your stack. Generate a flake. Ship it.

Scan any repository and produce a production-ready flake.nix in seconds.

---

flkr looks at your code (language, framework, package manager, lockfiles, build commands) and generates a thin flake.nix that delegates to the flkr-templates registry. The result is a reproducible Nix closure: sandboxed, cacheable, and ready to deploy.

No Nix knowledge required.

Usage

# Interactive wizard: detect, review, generate
flkr init

# Or go headless
flkr detect --json          # inspect what flkr sees
flkr generate               # write flake.nix
flkr generate --dry-run     # preview without writing

After generation:

nix run       # build and run
nix build     # build only
nix develop   # drop into a dev shell

What gets detected

Ecosystem	Package Managers	Frameworks
Go	gomod	Gin
Node.js	npm, yarn, pnpm	Next.js, Nuxt, Remix, Vite
Python	pip, poetry, pipenv, uv	Django, Flask, FastAPI
Rust	cargo	Actix
Ruby	bundler	Rails
Elixir	mix	Phoenix
PHP	composer	Laravel
Java	maven, gradle	Spring

Detection is layered: a base detector identifies the language and package manager, then specialized detectors refine the framework, build commands, ports, and system dependencies.

Example output

{
  description = "go-app -- generated by flkr";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flkr-templates.url = "github:narvanalabs/flkr-templates";
  };

  outputs = { self, nixpkgs, flkr-templates, ... }:
    flkr-templates.lib.mkApp {
      inherit nixpkgs;
      src = ./.;
      ecosystem = "go";
      version = "1.25.0";
      packageManager = "gomod";
      buildCommand = "go build -o myapp .";
      startCommand = "./myapp";
      port = 8080;
      vendorHash = "sha256-INXKKsT91oKPF7KYGTMKE2kCekumG8zuTylX2yEkIHQ=";
    };
}

The generated flake is config, not implementation. All build logic lives in flkr-templates: buildGoModule, buildRustPackage, mkDerivation, and friends.

Install

Nix (recommended)

# Run directly
nix run github:narvanalabs/flkr -- init

# Or install to profile
nix profile install github:narvanalabs/flkr

From source

git clone https://github.com/narvanalabs/flkr.git
cd flkr
make build    # produces ./flkr

Requires Go 1.25+.

go install

go install github.com/narvanalabs/flkr@latest

How it works

  your repo          flkr              flkr-templates
 ┌──────────┐    ┌──────────┐    ┌─────────────────────┐
 │ go.mod   │    │ Detect   │    │ buildGoModule        │
 │ package. │───▸│ Generate │───▸│ buildRustPackage     │───▸ Nix closure
 │ Cargo.   │    │ Hash     │    │ mkDerivation         │
 │ etc.     │    │          │    │ ...                  │
 └──────────┘    └──────────┘    └─────────────────────┘

1. Detect:scan the repo, build an AppProfile (language, framework, commands, ports, deps)
2. Generate:render flake.nix from the profile, compute vendorHash / cargoHash
3. Build:the generated flake delegates to flkr-templates.lib.mkApp for sandboxed, cacheable Nix builds

Project structure

cmd/               CLI (Cobra)
internal/
  detector/        Language & framework detectors
  generator/       flake.nix rendering
  nixhash/         Nix hash computation
  parser/          Config file parsers
  tui/             Interactive wizard (Bubble Tea)
pkg/flkr/          Public API

Part of Narvana

flkr is the detection engine for Narvana, a Nix-native PaaS.

flkr → flkr-templates → Attic → sops-nix → Deploy

Contributing

make all     # vet + test + build
make test    # tests only

License

Apache 2.0