Turbopack Error: Failed to write app endpoint /page

[saksham-joshi]

Turbopack version: d1bd5b58
Next.js version: 0.0.0

Error message:

Failed to write app endpoint /page

Caused by:
- [project]/app/globals.css [app-client] (css)
- failed to deserialize message
- invalid type: null, expected a string

Debug info:
- Execution of get_written_endpoint_with_issues_operation failed
- Execution of endpoint_write_to_disk failed
- Execution of <AppEndpoint as Endpoint>::output failed
- Failed to write app endpoint /page
- Execution of AppEndpoint::output failed
- Execution of AppProject::app_module_graphs failed
- Execution of *<AppEndpoint as Endpoint>::additional_entries failed
- Execution of *ModuleGraph::from_graphs failed
- Execution of SingleModuleGraph::new_with_entries_visited_intern failed
- [project]/app/globals.css [app-client] (css)
- Execution of primary_chunkable_referenced_modules failed
- Execution of <CssModuleAsset as Module>::references failed
- Execution of parse_css failed
- Execution of <PostCssTransformedAsset as Asset>::content failed
- Execution of PostCssTransformedAsset::process failed
- Execution of evaluate_webpack_loader failed
- failed to deserialize message
- invalid type: null, expected a string
    at .
         | v
       1 + {"type":"error","name":"CssSyntaxError","message":"tailwindcss: D:\\MY PROJECTS\\Senti-Vox\\site\\...:null,"methodName":"processTicksAndRejections","arguments":["native"],"lineNumber":7,"column":39}]}
         | ^

[vedant476]

This looks like a Tailwind CSS / PostCSS parsing issue rather than a Turbopack core bug. A few things to check:

Tailwind version mismatch — if you're on Tailwind v4, make sure you're using @tailwindcss/postcss in your postcss.config.js/mjs, not the old tailwindcss plugin directly. Mixing v3-style config with v4 causes this kind of null/invalid-type error during CSS processing.
Project path has spaces/special characters (D:\MY PROJECTS\Senti-Vox...). Turbopack on Windows can sometimes choke on paths with spaces. Try moving the project to a path without spaces (e.g. D:\projects\senti-vox) and see if the error goes away.
Check globals.css syntax — the error is specifically about parsing globals.css. Make sure there's no stray/invalid @import or custom at-rule that your current Tailwind/PostCSS version doesn't recognize.
Try deleting .next cache and node_modules/.cache, then run npm install again and restart the dev server.

If none of these help, could you share your postcss.config.js and the first few lines of globals.css? That'll narrow it down further.

[saksham-joshi]

Hi @vedant476, thanks for showing interest to help me out. I really appreciate it.

postcss.config.mjs:

const config = {
  plugins: {
    '@tailwindcss/postcss': {},
  },
}

export default config

globals.css

@import 'tailwindcss';

package.json

{
  "name": "senti-vox",
  "version": "1.0.0",
  "private": true,
  "scripts": {
    "dev": "bun --bun run next dev",
    "build": "bun --bun run next build",
    "start": "bun --bun run next start",
    "lint": "eslint",
    "format": "bunx prettier . --write",
    "format:check": "bunx prettier . --check",
    "fetch-schema": "bunx drizzle-kit pull"
  },
  "dependencies": {
    "@icons-pack/react-simple-icons": "^13.13.0",
    "@upstash/redis": "^1.38.2",
    "class-variance-authority": "^0.7.1",
    "clsx": "^2.1.1",
    "drizzle-orm": "^0.45.2",
    "lucide-react": "^0.562.0",
    "next": "16.3.1",
    "nodemailer": "^8.0.0",
    "postgres": "^3.4.9",
    "react": "19.2.3",
    "react-dom": "19.2.3",
    "tailwind-merge": "^3.4.0"
  },
  "devDependencies": {
    "@tailwindcss/postcss": "^4",
    "@types/node": "^20",
    "@types/nodemailer": "^7.0.9",
    "@types/pg": "^8.21.0",
    "@types/react": "^19",
    "@types/react-dom": "^19",
    "autoprefixer": "^10.5.4",
    "bun-types": "latest",
    "drizzle-kit": "^0.31.10",
    "eslint": "^9",
    "eslint-config-next": "16.1.1",
    "eslint-config-prettier": "^10.1.8",
    "postcss": "^8.5.26",
    "prettier": "^3.9.6",
    "tailwindcss": "^4.3.3",
    "typescript": "^5"
  },
  "ignoreScripts": [
    "sharp",
    "unrs-resolver"
  ],
  "trustedDependencies": [
    "sharp",
    "unrs-resolver"
  ]
}

tailwind.config.ts

import type { Config } from 'tailwindcss'
import { COLORS } from './lib/colors'

const config: Config = {
  content: ['./components/**/*.{js,ts,jsx,tsx}', './app/**/*.{js,ts,jsx,tsx}'],
  theme: {
    extend: {
      colors: {
        theme: {
          dark: COLORS.dark,
          light: COLORS.light,
        },
      },
      fontFamily: {
        sans: ['Inter', 'sans-serif'],
      },
    },
  },
  plugins: [],
}

export default config

[yotambarzilay]

I had a tailwing\postcss issue, downgraded postcss to 8.5.23 and is was resolved. maybe try that