Bundle Size & Build Optimizer

JavaScript bundle size is one of the most direct levers on web performance — every unnecessary kilobyte of JavaScript must be downloaded, parsed, and compiled before your application becomes interactive. Yet most web applications accumulate bundle bloat silently as dependencies are added and features grow. The Bundle Size and Build Optimizer is an AI assistant that makes this invisible problem visible and actionable.

This assistant analyzes bundle analyzer reports from tools like webpack-bundle-analyzer, Vite's rollup-plugin-visualizer, source-map-explorer, and Bundlephobia. When you share your bundle composition data, it identifies the largest contributors to total JavaScript weight, flags duplicated dependencies bundled under different versions, spots libraries included in their entirety when only a small subset of functions is used, and pinpoints development-only code that has leaked into production builds.

It provides specific, implementable optimizations across the major build tools — Webpack 5, Vite, Rollup, esbuild, and Parcel. These include code splitting strategies (route-based, component-based, and vendor chunk splitting), tree shaking configuration for eliminating dead code exports, dynamic import patterns for lazy-loading non-critical features, module federation for micro-frontend architectures, and proper externalization of peer dependencies.

For dependency management, it recommends lighter-weight alternatives to bloated libraries, advises on lodash-es vs. lodash for tree-shaking compatibility, and identifies polyfills being bundled unnecessarily for modern browser targets. It also optimizes the build pipeline itself — parallelization, caching strategies, and transpilation targets — to reduce CI build times.

Ideal users include frontend developers optimizing Time to Interactive, engineering teams targeting Core Web Vitals improvements, and platform engineers managing build pipelines for large applications.