Error: PostCSS plugin autoprefixer requires PostCSS 8. Update PostCSS or downgrade this plugin

user_12566640 0
Viewed 87431

I am getting this error whenever I run npm start. I tried a couple of fixes but none of them work for me. I tried to change the version of autoprefixer to 9.8.6 but it didn't work. Please help me with this issue

This is my package.json

{
  "name": "reactgallery",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^4.2.4",
    "@testing-library/react": "^9.5.0",
    "@testing-library/user-event": "^7.2.1",
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-scripts": "3.4.3"
  },
  "scripts": {
    "start": "npm run watch:css && react-scripts start",
    "build": "npm run build:css && react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject",
    "build:css": "postcss src/assets/tailwind.css -o src/assets/main.css",
    "watch:css": "postcss src/assets/tailwind.css -o src/assets/main.css"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "autoprefixer": "^9.8.6",
    "postcss-cli": "^7.1.2",
    "tailwindcss": "^1.8.10"
  }
}
postcss npm reactjs
12 Answers

Quick fix

Downgrade your autoprefixer to version 9, use

"autoprefixer": "^9.0.0"

in your dev dependencies.

More details

PostCSS was updated to version 8, however, PostCSS CLI has not yet been updated to handle PostCSS plugins which use the new PostCSS 8+ API. Autoprefixer uses the new PostCSS 8 API since version 10.

This is documented under known issues in the PostCSS GitHub page.

Once PostCSS CLI is updated to handle plugins that use the new PostCSS 8+ API, this will likely not be an issue. But until then, you may need to downgrade some PostCSS plugins to avoid errors.

user_107481250
user_111364490

I am not sure about this but can you try installing postcss as a dependency?

npm i postcss
user_107384590

Ok, to me was fixed removing package-lock.json and installing:

"tailwindcss": "^1.8.10"
"postcss-cli": "^7.1.0"
"autoprefixer": "^9.7.5"
user_87138480 
"dependencies": {
    "autoprefixer": "^9.8.6",
    "postcss": "^8.0.0",
    "postcss-cli": "^8.1.0",
    "tailwindcss": "npm:@tailwindcss/postcss7-compat@^2.0.2",
},

Dependecies object and version can be modified directly in the package.json file and it work

user_73055230

These steps worked for me. This was from github

npm uninstall tailwindcss postcss autoprefixer
npm install tailwindcss@latest postcss@latest autoprefixer@latest

npx tailwindcss init -p

npm uninstall tailwindcss postcss autoprefixer
npm install tailwindcss@npm:@tailwindcss/postcss7-compat postcss@^7 autoprefixer@^9
user_120101330

Based on documentation link are drop some support for old NodeJS and you must upgrade manually the packages. Example in my case for a project based on webpack need just to update those dependencies:

  "dependencies": {
    "autoprefixer": "^10.0.2",
    "postcss": "^8.1.7",
    "postcss-loader": "^4.0.4"
  }

So you do not need to downgrade autoprefixer :)

user_30906020

the following combo works as of Oct 2020

  ...
  "dependencies": {
    "autoprefixer": "^9.8.6",
    "postcss-cli": "^8.1.0",
    "tailwindcss": "^1.9.2"
  }
user_656940

Using the official solution fix for PostCSS 7 compatibility build

yarn remove tailwindcss postcss autoprefixer
yarn add -D tailwindcss@npm:@tailwindcss/postcss7-compat @tailwindcss/postcss7-compat postcss@^7 autoprefixer@^9
user_120018500

For Next.js 10 you just have to do

npm install tailwindcss@latest postcss@latest autoprefixer@latest

Source This issue here

user_146903850

I had this problem with Laravel-mix 5 and PostCSS 8 and Tailwind 2.
With Laravel-mix 6 (beta at the moment) this was solved.

npm install laravel-mix@next --save-dev
user_8992270

Its Simple,

npm install postcss@^8

It worked very well for me.

user_145685960
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