fFigma Leverages WebAssembly | Generated by AI
Figma leverages WebAssembly (Wasm) to supercharge its performance, making it a standout example of how this technology can transform web-based applications. At its core, Figma is a collaborative design tool that runs primarily in the browser, and it uses WebAssembly to execute critical, performance-intensive tasks at near-native speeds. Here’s how it works:
Figma’s engine is built in C++, a language known for its speed and efficiency but not natively supported by browsers. To bridge this gap, Figma compiles its C++ codebase into WebAssembly using Emscripten, a toolchain that converts C/C++ into Wasm binaries. These .wasm files are then loaded into the browser, where they handle the heavy lifting—things like rendering complex vector graphics, managing large design documents, and processing real-time updates across multiple users.
A big win from this approach is load time. Figma has reported that switching to WebAssembly cut its load time by over 3x compared to its earlier use of asm.js (a JavaScript subset for running C++ code). WebAssembly’s binary format is more compact and faster to parse than JavaScript, and once loaded, the browser caches the compiled machine code, so subsequent loads are even quicker. This is crucial for Figma, where users often juggle massive files and expect instant responsiveness.
The rendering engine is another key area where WebAssembly shines. Figma uses WebGL for GPU-accelerated graphics, but the logic driving this—think curve rendering, masking, blurs, and blend modes—is managed by the C++ code compiled to Wasm. This setup bypasses the browser’s HTML rendering pipeline, giving Figma fine-tuned control over performance and consistency across platforms. It’s why zooming and panning in Figma feel so smooth, even with thousands of layers.
Real-time collaboration also benefits. Figma’s multiplayer features rely on Conflict-Free Replicated Data Types (CRDTs) to sync changes instantly among users. While the CRDT logic itself might not all run in Wasm, the C++-powered engine handles the document state and updates efficiently, ensuring that collaborative edits don’t bog down the system. WebAssembly’s speed helps keep this seamless, even with dozens of collaborators.
There’s a hybrid architecture at play here: the core engine (C++/Wasm) manages the document and canvas, while the surrounding UI—like toolbars and menus—is built with JavaScript (now TypeScript + React). The two communicate via a bridge, with Wasm exporting functions that JavaScript can call, and vice versa. This division lets Figma optimize performance where it matters most while keeping the web-native flexibility of JavaScript for less compute-intensive tasks.
One catch: Figma doesn’t use WebAssembly uniformly across all browsers. Historically, it leaned on Wasm more in Firefox due to early Chrome bugs (e.g., lack of caching for translated Wasm code), though modern implementations have likely smoothed this out. Still, the C++-to-Wasm pipeline remains central to its architecture.
In short, Figma uses WebAssembly to bring desktop-grade performance to the browser, compiling its C++ core into efficient binaries that handle rendering, document management, and real-time sync. It’s a textbook case of Wasm enabling a web app to punch way above JavaScript’s weight class. Want to geek out more on the technical details or see how this compares to other tools?