I (with the help of an LLM-based agent) put together a Node-backed Tailwind CSS v4.3.1 wrapper for Linux RISC-V GNU systems:

This repo offers a prebuilt binary and a simple tailwindcss CLI wrapper. The binary is reproducible using a simple Docker-based workflow.

This came out of trying to run a Phoenix app on a Scaleway RISC-V server running Ubuntu 24.04. Phoenix’s tailwind package could not download an official Tailwind binary for riscv64-unknown-linux-gnu, and Tailwind’s official standalone binary path depends on Bun. Bun does not currently provide a Linux RISC-V target, so the official single-file Tailwind standalone binary is not available there.

DISCLAIMER: I built this to scratch an itch for a weekend project, and have only run this in a :dev config environment. Everything appears to work, but this is presented as an experimental proof-of-concept, and nothing more. I just thought it was cool and wanted to share it.

This package is not Tailwind’s official standalone binary. It is a self-contained tarball distribution with:

• A wrapper (bin/tailwindcss) that provides a compatible interface for the :tailwind Mix package.
• bundled Node
• pinned @tailwindcss/cli / tailwindcss
• the Linux RISC-V native addons needed by the Node CLI

It does not need npm at runtime, and it does not require app-local Tailwind node_modules. It does need the extracted package directory to remain intact, because bin/tailwindcss is a wrapper around the bundled runtime.

For Phoenix, the important part is to point the Elixir Tailwind config at the wrapper and disable the version check.

config/config.exs

  config :tailwind,
    version: "4.3.1",
+   path: "/path/to/tailwindcss-riscv64-linux-gnu-v4.3.1/bin/tailwindcss",
+   version_check: false,
    hello_phoenix: [
      args: ~w(
        --input=assets/css/app.css
        --output=priv/static/assets/css/app.css
      ),
      cd: Path.expand("..", __DIR__),
      env: %{"NODE_PATH" => [Path.expand("../deps", __DIR__), Mix.Project.build_path()]}
   ]

Also remove tailwind.install --if-missing, because the Elixir Tailwind downloader does not provide a Linux RISC-V binary.

mix.exs

defp aliases do
  [
-   "assets.setup": ["tailwind.install --if-missing", "esbuild.install --if-missing"],
+   "assets.setup": ["esbuild.install --if-missing"],
    "assets.build": ["compile", "tailwind hello_phoenix", "esbuild hello_phoenix"],
    "assets.deploy": [
      "tailwind hello_phoenix --minify",
      "esbuild hello_phoenix --minify",
      "phx.digest"
    ]
  ]
end

I built and verified this on Ubuntu 24.04 LTS on a Scaleway RISC-V server. Phoenix asset build/deploy worked, and the rendered page was styled correctly in the browser, and works correctly with Phoenix’s built-in hot reload feature.

The long-term upstream fix is still Bun support for Linux RISC-V, or a different official Tailwind standalone build path that does not depend on Bun. Until then, this gives Phoenix apps a technically-usable Tailwind v4 path on Linux RISC-V.