Supported Runtimes

When using the Nixpacks build mode, Apply.Build automatically detects your application's runtime based on files in your repository. If you use the Dockerfile build mode, you have full control over the runtime — see Deployments for details.

Languages and runtimes

Runtime	Detected by	Versions
Clojure	`project.clj` or `build.clj`	JDK 8 (default), 11, latest
COBOL	`.cbl` files	Latest
Crystal	`shard.yml`	Latest
C#/.NET	`*.csproj`	Via `global.json` or `NIXPACKS_CSHARP_SDK_VERSION`
Dart	`pubspec.yaml`	Latest
Deno	`deno.json` or `deno.jsonc`	Latest
Elixir	`mix.exs`	Latest (default), 1.17, 1.16, 1.15, 1.14, 1.13, 1.12, 1.11, 1.10, 1.9
F#	`*.fsproj`	Via `global.json` or `NIXPACKS_CSHARP_SDK_VERSION`
Gleam	`gleam.toml` and `manifest.toml`	From `manifest.toml`
Go	`main.go`	1.18–1.23 (default 1.22)
Haskell	`package.yaml` and `.hs` files	Via Stack
Java	`pom.xml` or `gradlew`	JDK 8, 11, 17 (default), 19, 20, 21
Lunatic	`Cargo.toml` with `runner = "lunatic"`	Latest stable
Node.js	`package.json`	16, 18 (default), 20, 22, 23
PHP	`composer.json` or `index.php`	8.1, 8.2 (default), 8.3, 8.4
Python	`main.py`, `requirements.txt`, `pyproject.toml`, or `Pipfile`	2.7, 3.8–3.13 (default 3.11)
Ruby	`Gemfile`	Via `.ruby-version` or `Gemfile`
Rust	`Cargo.toml`	Latest stable (default), any via rust-overlay
Scala	`build.sbt`	JDK 8, 11, 17 (default), 19, 20, 21
Swift	`Package.swift`	3.1–5.8 (default 5.8)
Zig	`build.zig`	Latest

Static sites

Static files are served automatically when any of the following are found: a Staticfile, ./public, ./dist, ./index, or ./index.html.

Specifying a version

You can pin a runtime version using standard version files:

Node.js — .node-version, .nvmrc, or engines field in package.json
Python — .python-version, runtime.txt, or .tool-versions
Go — go directive in go.mod
Ruby — .ruby-version or Gemfile
Swift — .swift-version or swift-tools-version in Package.swift
Elixir — .elixir-version or mix.exs

See the Nixpacks docs for full details on each provider.