ESM CDN

A global ESM content delivery network that transforms npm packages, JSR modules, GitHub repositories, and pkg.pr.new preview builds into ES modules that can be imported directly in browsers and Deno without any build step or installation. The platform serves over 8.2 billion module requests per month with edge caching powered by Cloudflare across global regions. The CDN intelligently rewrites CommonJS modules into ES modules, resolves dependency trees automatically, and provides query parameters for fine-grained control including deps for specifying exact dependency versions, alias for substituting one package for another such as preact for react, bundle for controlling bundling strategy, exports for tree-shaking specific named exports to reduce payload size, dev for development builds with NODE_ENV set to development, worker for loading modules as web workers, raw for serving untransformed source files, and target for specifying ES build targets from es2015 to es2024. The TSX feature provides a 1 kilobyte script that enables writing TSX and JSX directly in HTML documents with type text/babel or text/tsx script tags, with server-side compilation and edge caching. Import maps are fully supported through the external query, allowing bare specifiers like importing React to resolve through browser-native import maps rather than URL imports. The platform is Deno-compatible, resolving Node built-in modules such as fs, os, and net, and serving TypeScript definitions through the X-TypeScript-Types header for type checking and autocomplete in Deno. The project is maintained by ije on GitHub under the MIT license, with sponsorship from Deno, Val Town, Anthony Fu, and Guillermo Rauch.