JavaScript & Web API Tools
Speculation Rules Generator
Generate Speculation Rules JSON for prerendering and prefetching pages in Chrome and Edge.
Tools
Free JavaScript & Web API Tools
Generate and test browser API snippets for navigation, workers, performance, URLs, regex, transport, reporting, and modern interactions.
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JavaScript & Web API Tools you can use now
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JavaScript & Web API Tools
Navigation API Router Snippet Generator
Generate JavaScript code for client-side routing using the Navigation API. Intercept navigations, match route patterns, and update content without full page reloads.
JavaScript & Web API Tools
Service Worker Module Template Generator
Generate an ES module service worker with configurable cache strategies, precache URL list, auto-activation, and offline fallback support.
JavaScript & Web API Tools
Reporting API Header Generator
Generate Report-To and Reporting-Endpoints HTTP headers for Nginx and Apache, plus CSP Reporting and Network Error Logging configuration.
JavaScript & Web API Tools
URLPattern Tester
Test URL patterns with named groups, wildcards, and regex constraints. Generate JavaScript URLPattern code and see live match results with extracted parameters for multiple test URLs.
JavaScript & Web API Tools
scrollend Event Snippet Generator
Generate JavaScript snippets using the scrollend event that fires when scrolling fully completes including momentum and inertia, with debounce comparison to show why native scrollend is more accurate.
JavaScript & Web API Tools
PerformanceObserver Snippet Generator
Generate JavaScript snippets using PerformanceObserver to monitor Core Web Vitals (LCP, INP, CLS, FID, FCP, TTFB) and other performance metrics in real-time with good/needs-improvement/poor threshold classifications.
JavaScript & Web API Tools
RegExp.escape() Helper
Escape special regex characters in user input using the native RegExp.escape() method. Generate safe dynamic regex patterns with comparison to old manual escaping.
JavaScript & Web API Tools
Intl.DurationFormat Generator
Format durations with locale-aware Intl.DurationFormat. Supports long, short, narrow, and digital styles in 6+ locales. No more moment-duration-format.
JavaScript & Web API Tools
Custom Highlight API Generator
Generate JavaScript and CSS snippets for the Custom Highlights API to style arbitrary text ranges without modifying the DOM. Uses CSS.highlights registry and ::highlight() pseudo-element for find-in-page, syntax highlighting, and search results.
JavaScript & Web API Tools
WebTransport URL Template Helper
Generate a JavaScript WebTransport connection snippet with URL template, bidirectional streams, and datagram support for low-latency client-server communication over HTTP/3 (QUIC).
What this collection helps with
Modern browser APIs can replace large libraries, but their event models, fallback requirements, and support boundaries are easy to miss. These tools produce focused examples for one API at a time so you can inspect the code, understand its assumptions, and adapt it to your application.
Best for
- Frontend developers evaluating a modern browser API.
- Static-site authors adding small progressive enhancements.
- Teams preparing copyable examples with explicit fallback notes.
Common use cases
- Create Navigation API, service worker, or PerformanceObserver starter code.
- Test URLPattern, RegExp.escape(), and locale-aware duration formatting.
- Prepare Reporting API, WebTransport, or interaction event snippets.
Task guide
Choose an API based on the browser capability you need, then verify its support and fallback behavior before adopting the generated snippet. Test success, error, cancellation, and unsupported-browser paths. Keep progressive enhancements optional so core content and navigation remain usable when the API is unavailable.
Publishing checklist
- Check current browser support for the API and every method used by the snippet.
- Add feature detection before calling newer browser APIs.
- Handle errors, abort signals, timeouts, and cleanup where applicable.
- Test keyboard, reduced-motion, and assistive-technology behavior for UI APIs.
- Confirm the page still works when the enhancement is unavailable.
FAQ
Questions about javascript & web api tools
Do these snippets need a build tool?
Most examples use browser-native JavaScript and can run without a framework. Module-based examples may need to be served over HTTP rather than opened directly from a local file.
How should I handle unsupported browsers?
Use feature detection, preserve a functional baseline, and add the API as a progressive enhancement. Provide a documented fallback when the feature controls essential behavior.
Are browser support claims permanent?
No. Browser APIs evolve, and support can change between releases. Review official compatibility information before deploying generated code.