{"id":20746,"library":"webpack-dev-server","title":"webpack-dev-server","description":"A development server that provides live reloading for webpack projects, using webpack-dev-middleware for fast in-memory asset access. Current stable version is 5.2.3 (released January 2026). Active maintenance with frequent patch releases. Major differentiating features include: live reloading, HMR, overlay for runtime errors, proxy for API forwarding, HTTPS support, and TypeScript type definitions. Requires Node >= 18.12.0 and webpack ^5.0.0 as peer dependency. Breaking changes in v5 include stricter CORS and WebSocket security, removal of certain options like `inline` and `lazy`, and migration from webpack-cli v4 to v5.","status":"active","version":"5.2.3","language":"javascript","source_language":"en","source_url":"https://github.com/webpack/webpack-dev-server","tags":["javascript","typescript"],"install":[{"cmd":"npm install webpack-dev-server","lang":"bash","label":"npm"},{"cmd":"yarn add webpack-dev-server","lang":"bash","label":"yarn"},{"cmd":"pnpm add webpack-dev-server","lang":"bash","label":"pnpm"}],"dependencies":[{"reason":"peer dependency - core bundler required","package":"webpack","optional":false}],"imports":[{"note":"Use 'webpack serve' CLI command; 'webpack-dev-server' bin is deprecated in v5.","wrong":"npx webpack-dev-server","symbol":"webpack-dev-server","correct":"npx webpack serve"},{"note":"ESM-only since v5; default export for API usage.","wrong":"const WebpackDevServer = require('webpack-dev-server');","symbol":"WebpackDevServer","correct":"import WebpackDevServer from 'webpack-dev-server';"},{"note":"TypeScript users should import the server-specific Configuration type from 'webpack-dev-server'.","wrong":"import { Configuration } from 'webpack';","symbol":"Configuration","correct":"import type { Configuration } from 'webpack-dev-server';"}],"quickstart":{"code":"// webpack.config.js (ESM)\nimport WebpackDevServer from 'webpack-dev-server';\nimport webpack from 'webpack';\n\nconst compiler = webpack({ /* webpack config */ });\nconst devServerOptions = { port: 3000, hot: true };\nconst server = new WebpackDevServer(devServerOptions, compiler);\n\nasync function start() {\n  await server.start();\n  console.log('Dev server running on http://localhost:3000');\n}\nstart();","lang":"typescript","description":"Shows programmatic usage of WebpackDevServer with ESM imports, async start, and hot module replacement enabled."},"warnings":[{"fix":"Configure allowedHosts or ensure Origin header matches Host for WebSocket connections.","message":"Cross-origin requests are not allowed unless allowed by Access-Control-Allow-Origin header; requests with IP addresses in Origin header are not allowed to connect to WebSocket server unless configured by allowedHosts.","severity":"breaking","affected_versions":">=5.2.1"},{"fix":"Upgrade to webpack-dev-server >=5.0.4 (or >=4.15.2 for v4).","message":"Security: bump webpack-dev-middleware to address directory traversal vulnerability.","severity":"breaking","affected_versions":"<5.0.4"},{"fix":"Use webpack-dev-server v4 or adjust config (e.g., use 'client.webSocketURL' instead of 'inline').","message":"Options 'inline', 'lazy', 'noInfo', 'reporter', 'quiet', 'colors' are removed in v5.","severity":"deprecated","affected_versions":">=5.0.0"},{"fix":"Run 'npx webpack serve' instead, which integrates with webpack-cli.","message":"Using 'webpack-dev-server' bin directly (e.g., npx webpack-dev-server) is deprecated in favor of 'webpack serve'.","severity":"gotcha","affected_versions":">=5.0.0"},{"fix":"Use 'import type { Configuration } from 'webpack-dev-server';' not from 'webpack'.","message":"TypeScript types for Configuration require explicit import from 'webpack-dev-server'.","severity":"gotcha","affected_versions":">=5.0.0"}],"env_vars":null,"last_verified":"2026-04-25T00:00:00.000Z","next_check":"2026-07-24T00:00:00.000Z","problems":[{"fix":"Run 'npm install --save-dev webpack-dev-server' in project directory.","cause":"Missing local installation or using deprecated CLI command without local webpack-dev-server.","error":"Cannot find module 'webpack-dev-server'"},{"fix":"Change port in config (e.g., --port 3000) or kill process using the port.","cause":"Port 8080 already in use by another process.","error":"Error: listen EADDRINUSE :::8080"},{"fix":"Remove deprecated options. See migration guide: https://github.com/webpack/webpack-dev-server/releases/tag/v5.0.0","cause":"Using a deprecated option (e.g., 'inline', 'lazy') in v5 config.","error":"Invalid configuration object. webpack-dev-server has been initialized using a configuration object that does not match the API schema."}],"ecosystem":"npm","meta_description":null,"install_score":null,"install_tag":null,"quickstart_score":null,"quickstart_tag":null}