Suggest an editImprove this articleRefine the answer for “What is HMR?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**HMR (Hot Module Replacement)** is a Webpack mechanism that lets you update individual application modules without a full page reload. **Key point:** the browser replaces only the changed piece of code, preserving the application's state.Shown above the full answer for quick recall.Answer (EN)Image**HMR (Hot Module Replacement)** is a Webpack mechanism that lets you update individual application modules **without a full page reload**. Changes are applied "on the fly", right after the file is saved, and the browser replaces only the changed piece of code. **What HMR gives you:** 1. **Instant visual feedback** - the interface updates without reloading. 2. **Preserving application state** - for example, an open tab, entered text, or component state is not reset. 3. **Faster development** - the build happens faster and does not distract from the process. **How it works under the hood:** the Webpack Dev Server tracks changes in files, rebuilds only the changed module, and sends it to the browser over a WebSocket connection. The browser replaces the updated module right inside the running application.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.