BundleSpy

Analyze JavaScript bundle composition to identify bloat and optimization opportunities

Code & DevelopmentFreemium

BundleSpy analyzes compiled JavaScript bundles to show exactly which source files, npm packages, and polyfills contribute to final bundle size, with interactive treemaps and dependency chains showing why each module was included. The tool identifies duplicate packages included at different versions, unused exports that tree-shaking missed, and polyfills that are unnecessary for the target browser matrix. Frontend performance engineers use it to set and enforce bundle size budgets while product teams use it to understand the size cost of adding new dependencies.

Key Features

• ✓Interactive treemaps
• ✓Duplicate detection
• ✓Tree-shaking gaps
• ✓Polyfill audit
• ✓Size budget enforcement