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When I announced Bonsai two days ago, the goal was to eliminate Node.js from this site’s build pipeline by replacing html-minifier with a pure Swift alternative. That got rid of one Node dependency, but the biggest one remained: Tailwind CSS itself. The build process still shelled out to pnpm tailwindcss to compile CSS. So I built SwiftTailwind.

What it does

SwiftTailwind wraps the official Tailwind CSS standalone CLI, which is a self-contained binary that doesn’t need Node.js. The package downloads the correct binary for your platform (macOS or Linux, ARM or x64), validates its SHA-256 checksum against the official release, caches it at ~/.swifttailwind/, and runs it via Foundation.Process. No Node, no npm, no node_modules.

It supports both Tailwind v3 and v4.

Usage

Add it to your Package.swift:

dependencies: [
  .package(url: "https://github.com/loopwerk/SwiftTailwind", from: "1.0.0"),
],
targets: [
  .executableTarget(
    name: "YourApp",
    dependencies: ["SwiftTailwind"]
  ),
]

Then compile your CSS:

import SwiftTailwind
let tailwind = SwiftTailwind(version: "3.4.17")
try await tailwind.run(
  input: "content/static/input.css",
  output: "content/static/output.css",
  options: .minify
)

That’s it. Paths can be relative to your project root (detected automatically from Package.swift) or absolute.

In this website I run SwiftTailwind right before building the rest of the website. But instead of Tailwind living in pnpm scripts and a justfile, it’s now all part of the same Swift pipeline.

Why not just use the standalone CLI directly?

You could download the Tailwind standalone binary yourself and call it from a shell script. SwiftTailwind saves you from dealing with platform detection, downloading the right binary, verifying checksums, caching across versions, and wiring up Foundation.Process. It’s a single import and two lines of code.

Inspiration

SwiftTailwind is inspired by SwiftyTailwind, which is now archived and no longer maintained. SwiftTailwind is a fresh implementation with checksum verification, cleaner error handling, and full Sendable conformance for Swift concurrency.

Try it out

SwiftTailwind is available on GitHub: loopwerk/SwiftTailwind. It works with any Swift project that needs Tailwind CSS, not just Saga.

Announcing SwiftTailwind