Install Tailwind CSS with Phoenix

Setting up Tailwind CSS in a Phoenix project.

Create your project

Start by creating a new Phoenix project if you don't have one set up already. You can follow their installation guide to get up and running.

Terminal

mix phx.new myproject
cd myproject

Install the Tailwind plugin

Add the Tailwind plugin to your dependencies and run mix deps.get to install it.

mix.exs

defp deps do
  [
    # …
    {:tailwind, "~> 0.3", runtime: Mix.env() == :dev},
  ]
end

Configure the Tailwind plugin

In your config/config.exs file you can set which version of Tailwind CSS you want to use and customize your asset paths.

config.exs

config :tailwind,
  version: "4.0.0",
  myproject: [
    args: ~w(
      --input=assets/css/app.css
      --output=priv/static/assets/app.css
    ),
    cd: Path.expand("..", __DIR__)
  ]

Update your deployment script

Configure your assets.deploy alias to build your CSS on deployment.

mix.exs

defp aliases do
  [
    # …
    "assets.deploy": [
      "tailwind myproject --minify",
      "esbuild myproject --minify",
      "phx.digest"
    ]
  ]
end

Enable watcher in development

Add Tailwind to your list of watchers in your ./config/dev.exs file.

dev.exs

watchers: [
  # Start the esbuild watcher by calling Esbuild.install_and_run(:default, args)
  esbuild: {Esbuild, :install_and_run, [:myproject, ~w(--sourcemap=inline --watch)]},
  tailwind: {Tailwind, :install_and_run, [:myproject, ~w(--watch)]}
]

Install Tailwind CSS

Run the install command to download the standalone Tailwind CLI.

Terminal

mix tailwind.install

Import Tailwind CSS

Add an @import to ./assets/css/app.css that imports Tailwind CSS.

app.css

@import "tailwindcss";

Remove the default CSS import

Remove the CSS import from ./assets/js/app.js, as Tailwind is now handling this for you.

app.js

// Remove this line if you add your own CSS build pipeline (e.g postcss).
import "../css/app.css"

Start your build process

Run your build process with mix phx.server.

Terminal

mix phx.server

Start using Tailwind in your project

Start using Tailwind’s utility classes to style your content.

index.html.heex

<h1 class="text-3xl font-bold underline">
  Hello world!
</h1>