SharePoint Framework (SPFx) is a powerful platform for building client-side web parts and extensions. However, one common challenge developers face is slow build times during development, especially for large projects. Fast-Serve is a helper library that solves this problem by speeding up the build and serve process.
What is Fast-Serve?
Fast-Serve is a development-time optimization tool for SPFx projects. It integrates with the SPFx Gulp build pipeline to:
Rebuild only the files that have changed (incremental build).
Keep the local development server running continuously.
Automatically reload the browser when changes are detected.
Essentially, it reduces wait time and improves the developer experience.
Why Use Fast-Serve?
Without Fast-Serve
Every change triggers a full project rebuild, which can take minutes in large projects.
The local server may stop and restart during builds.
Browser refresh is delayed until the full rebuild finishes.
With Fast-Serve
Only changed files are rebuilt.
The server stays running, no downtime.
Browser reloads happen instantly.
How to Add Fast-Serve to Your SPFx Project
Install the Fast-Serve Package
npm install spfx-fast-serve-helpers --save-dev
Update gulpfile.js
'use strict';
const build = require('@microsoft/sp-build-web');
// Optional: suppress SASS warnings
build.addSuppression(`Warning - [sass] The local CSS class 'ms-Grid' is not camelCase and will not be type-safe.`);
// Add Fast-Serve
const { addFastServe } = require('spfx-fast-serve-helpers');
addFastServe(build);
// Initialize SPFx build system
build.initialize(require('gulp'));
Fast-Serve will now
Watch your files for changes.
Rebuild only the modified files.
Reload your browser automatically.
Run Gulp Serve
//Start Local Development Server
gulp serve
How Fast-Serve Works Internally
Hooks into Gulp tasks: Wraps SPFx build tasks to detect changes.
File watching: Monitors TypeScript, CSS, SASS, and asset files.
Incremental build: Recompiles only changed files.
Hot reload: Refreshes the browser instantly without restarting the server.
Comparision
| Feature | Normal SPFx Serve | Fast-Serve |
|---|
| Build type | Full rebuild | Incremental rebuild |
| Server restart | May happen | Not required |
| Browsers reload | After full rebuild | Immediate |
| Speed | Slow for large projects | Fast |
Benefits of Fast-Serve
Saves time during development.
Improves developer productivity.
Compatible with all SPFx project types (web parts, extensions, applications).
Conclusion
Fast-Serve is a must-have tool for SPFx developers to speed up local development. By integrating Fast-Serve into your gulpfile.js, you can focus on writing code instead of waiting for long builds.