Everything you need.
Nothing you don't.
A single script tag is all it takes to unlock the modern web platform for every visitor.
Instant setup
One <script> tag. No bundler, no CLI, no config. Start in under 60 seconds.
Zero dependencies
The entire library is self-contained. No external packages, no version conflicts.
Minimal footprint
Carefully hand-tuned to stay as small as possible — only what each browser actually needs.
Spec-compliant
Every polyfill strictly follows the ECMAScript and WHATWG specifications.
CDN-ready
Served from our global edge network with long-lived caching and CORS headers included.
Open source
MIT-licensed and fully auditable on GitHub. Community PRs and issues welcome.
Add it in seconds
Paste the snippet below into your HTML <head> and you're done.
<!-- Load js-deliver from the CDN --> <script src="https://js-deliver.com/v2/polyfill.min.js" crossorigin="anonymous"></script>
For advanced options, self-hosting, and contributing, see the project on GitHub.
What's included
A curated set of polyfills that close the most common compatibility gaps.
- Array.prototype.flat
- Array.prototype.flatMap
- String.prototype.replaceAll
- String.prototype.at
- Array.prototype.at
- Object.fromEntries
- Object.hasOwn
- Promise.allSettled
- queueMicrotask
- structuredClone
- globalThis
- + more on GitHub