This content originally appeared on DEV Community and was authored by Yogesh Bamanier
Learn how React leverages Virtual DOM and Fiber Node to efficiently update your UI and keep apps smooth. ✨
When I first started diving deep into React, I kept wondering: “Are Virtual DOM and Fiber Node the same thing?” 🤔
The short answer is no, but they are closely related, like two teammates ⚽ with different roles in a match.
🔹 Are They the Same? What’s the Relation? 🧩
- Virtual DOM (VDOM) 🖼️: a snapshot of your UI in memory.
- Fiber Node 🔗: the task manager for React, tracking updates to each component individually.
Think of it this way:
Virtual DOM = what your UI looks like in memory
Fiber Node = how React decides what to update, when, and in what order 🕒
They work hand-in-hand: React uses the Virtual DOM to calculate changes, and Fiber breaks this work into units that can be scheduled efficiently ⚡, keeping large UI updates smooth.
🔹 Virtual DOM 🖼️
The Virtual DOM is an in-memory representation of the real DOM. React updates this virtual copy first, instead of touching the browser DOM directly.
How It Works:
- React renders the UI to a Virtual DOM tree 🌳
- On state or props update, a new Virtual DOM tree is created 🔄
- React diffs the old and new VDOM to find changes 🔍
- Only the changed parts are patched to the real DOM 🏗️
Pros:
- ⚡ Performance optimization – fewer direct DOM updates
- 🖌️ Declarative UI – React computes changes abstractly
- 🧠 Easier to reason about state updates and re-rendering
🔹 Fiber Node 🔗
Fiber is React’s reconciliation engine introduced in React 16.
Each component corresponds to a Fiber Node, a unit of work storing metadata like:
- 🏷️ Component type
- 📝 Props and state
- 🔗 Parent, child, sibling pointers
- ⚠️ Effect tags (tracking updates)
Why Fiber?
Previously, React’s diffing blocked the main thread ⏳ for large trees. Fiber solves this by:
- Splitting updates into small units ✂️
- Prioritizing important updates (animations vs background tasks) 🎯
- Pausing, aborting, or resuming work for smooth UIs 🛑➡️▶️
Example Fiber Tree:
This content originally appeared on DEV Community and was authored by Yogesh Bamanier
Yogesh Bamanier | Sciencx (2025-09-23T19:24:04+00:00) ⚡ React Internals: Virtual DOM 🖼️ vs Fiber Node 🔗 for Performance Explained. Retrieved from https://www.scien.cx/2025/09/23/%e2%9a%a1-react-internals-virtual-dom-%f0%9f%96%bc%ef%b8%8f-vs-fiber-node-%f0%9f%94%97-for-performance-explained-2/
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