Understanding Build Helpers in Nix

# Build helpers {#part-builders} A build helper is a function that produces derivations. :::{.warning} This is not to be confused with the [`builder` argument of the Nix `derivation` primitive](https://nixos.org/manual/nix/unstable/language/derivations.html), which refers to the executable that produces the build result, or [remote builder](https://nixos.org/manual/nix/stable/advanced-topics/distributed-builds.html), which refers to a remote machine that could run such an executable. ::: Such a function is usually designed to abstract over a typical workflow for a given programming language or framework. This allows declaring a build recipe by setting a limited number of options relevant to the particular use case instead of using the `derivation` function directly. [`stdenv.mkDerivation`](#part-stdenv) is the most widely used build helper, and serves as a basis for many others. In addition, it offers various options to customize parts of the builds. There is no uniform interface for build helpers. [Trivial build helpers](#chap-trivial-builders) and [fetchers](#chap-pkgs-fetchers) have various input types for convenience. [Language- or framework-specific build helpers](#chap-language-support) usually follow the style of `stdenv.mkDerivation`, which accepts an attribute set or a fixed-point function taking an attribute set. ```{=include=} chapters build-helpers/fixed-point-arguments.chapter.md build-helpers/fetchers.chapter.md build-helpers/trivial-build-helpers.chapter.md build-helpers/testers.chapter.md build-helpers/dev-shell-tools.chapter.md build-helpers/special.md build-helpers/images.md hooks/index.md languages-frameworks/index.md packages/index.md ```

Build helpers are functions designed to produce Nix derivations, abstracting common build workflows for various programming languages and frameworks. Unlike the `builder` argument or remote builders, build helpers simplify declaring build recipes by allowing users to set a limited number of options instead of directly using the `derivation` function. `stdenv.mkDerivation` is the most widely used build helper, serving as a foundation for many others. While there's no uniform interface, many language- or framework-specific build helpers follow the style of `stdenv.mkDerivation`, accepting an attribute set or a fixed-point function.