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Launch Handler API Demo - Online Control App Launch Behavior

Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.

Developer Tools API demo Launch Handler PWA

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File Handle API Demo - Online Persistent File Access

Use the File System Access API with file handles for persistent read/write. Learn incremental saving patterns.

API API File Handle open save

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Compression Streams API Demo - Online Gzip/Deflate Raw

Compress and decompress text using the browser's native Compression Streams API. See the binary output size.

API API Compression Streams deflate gzip

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Content Indexing API Test - Online Add to Device's Media Feed

Test the Content Indexing API to add a page to the device's content feed. See how your PWA integrates with the OS.

Developer Tools API Content Indexing PWA test

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Font Loading API Demo - Online Wait for Fonts Ready

Use the document.fonts API to check if a font is loaded. Watch the ready promise. Avoid FOUT. JavaScript demo.

Developer Tools API demo document.fonts Font Loading

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Resource Timing Viewer - Online See All Asset Loads

List all resources loaded by the current page and their detailed timing breakdown. In‑browser waterfall.

Developer Tools API performance Resource Timing waterfall

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Navigation Timing API Viewer - Online Page Load Breakdown

See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.

Developer Tools API Navigation Timing page load performance

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Broadcast Channel API Demo - Online Cross‑Tab Communication

Open the same page in two tabs and send messages between them. See real‑time cross‑tab communication. Learn the API.

API API Broadcast Channel messaging tabs

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Selection & Range API Demo - Online Get/Set Selection

Select text and see the Selection object properties. Create ranges programmatically. Understand how rich‑text editors work.

Developer Tools API demo Range Selection

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Permissions Query API Demo - Online Check All APIs

Query the permission state of camera, microphone, geolocation, and more. See the response and learn the API.

API API demo Permissions query

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API Request Builder - Online Test REST Endpoints

Select HTTP method, set headers, and body. Send requests and see the full response. Lightweight Postman alternative.

API API request REST test

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Browser Feature Support Detector - Online Check Your Device

See a comprehensive table of which modern web APIs your current browser supports. Includes WebGPU, AVIF, and more.

Developer Tools API browser feature detection support

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Navigation Timing API Viewer - Online Page Load Breakdown

See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.

Developer Tools API Navigation Timing page load performance

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Gamepad Tester - Online Button & Axis Visualizer

Connect a game controller and see every button press, axis movement, and vibration test. Uses the Gamepad API.

Developer Tools API button gamepad tester

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Constraint Validation API Tester - Online Form Debug

Test required, pattern, minlength etc. See validity states and custom error messages. Learn browser‑native validation.

Developer Tools API Constraint Validation debug form

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Pointer Events Playground - Online Mouse, Touch & Pen

Unified input demo: see pressure, tilt, and type from any pointer. Compare pointerType values. Essential for drawing apps.

API API pen Pointer Events touch

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Mutation Observer Tester - Online DOM Change Watcher

Modify the DOM via buttons and see MutationRecords logged. Understand childList, attributes, and subtree options.

Developer Tools API DOM Mutation Observer watch

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Resize Observer Playground - Online Watch Element Size

Drag to resize a box and see the Resize Observer callback fire. Get contentRect and borderBoxSize. Learn the API.

Developer Tools API playground Resize Observer size

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Web Animations API Sandbox - Online JS Animation Editor

Write JavaScript using element.animate() and see the result in a live preview. Compare with CSS keyframes. Debugger included.

Developer Tools API JavaScript playground Web Animations

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Screen Wake Lock Tester - Online Keep Screen On

Toggle a screen wake lock to prevent the device from dimming or sleeping. See the lock state and learn the API.

Developer Tools API battery Screen Wake Lock test

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Built-in Translation API Demo - Online On‑Device Translate

Test the experimental Translation API to translate text between languages directly in the browser, without cloud calls. Check support and copy the JavaScript starter.

AI API Chrome demo Translation

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ImageDecoder API Demo - Online Progressive Decode

Decode an image progressively using the ImageDecoder API. See partial results and metadata. Modern alternative to <img>.

Developer Tools API decode ImageDecoder JPEG

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WebCodecs Video Frame Reader - Online Decode & Display

Decode individual video frames from a local file using the VideoDecoder API. Step through frames. Cutting‑edge browser feature.

Developer Tools API decoder VideoFrame WebCodecs

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Shared Storage API Demo - Online Cross‑Site Data

Write to shared storage and run a worklet to process data. Learn the privacy‑preserving alternative to third‑party cookies.

Developer Tools API privacy sandbox Shared Storage

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Private State Token Demo - Online Anti‑Fraud Test

Issue and redeem Private State Tokens (formerly Trust Tokens). Understand how they help detect bots without cookies.

API anti‑fraud API privacy trust token

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FedCM Demo - Online Federated Credential Management

Experiment with the Federated Credential Management API. Simulate a sign‑in flow without third‑party cookies. Privacy‑first.

API API FedCM identity sign‑in

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Get Installed Related Apps Demo - Online PWA Detection

Check if your related native or PWA app is installed. See the API in action and copy the code.

Developer Tools API detection getInstalledRelatedApps PWA

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Web Share Level 2 Tester - Online Share Files

Test sharing multiple files (images, PDFs) using the Web Share API. Check if the browser supports file sharing. Demo page.

API API files share Web Share

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Periodic Background Sync Registration - Online PWA Tool

Register a periodic background sync with a minimum interval. See the registration state and tags. Keep content fresh.

Developer Tools API Periodic Sync PWA registration

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Background Sync API Tester - Online Offline Queue

Register a one‑off background sync and see it fire when connectivity returns. Debug service worker sync logic.

Developer Tools API Background Sync offline service worker

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Picture‑in‑Picture Tester - Online Float Video Anywhere

Open a test video in Picture‑in‑Picture mode. Control entering and leaving PiP. Copy the code snippet for your own app.

Developer Tools API float Picture‑in‑Picture video

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Media Session API Demo - Online Now Playing Widget

Set media metadata and play/pause controls for the OS media widget. Test action handlers. Perfect for web audio apps.

Developer Tools API Media Session metadata now playing

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Bluetooth Battery Monitor - Online Read Device Levels

Connect to a BLE device and read its Battery Service characteristic. See the charge level in a gauge.

Developer Tools API battery BLE Bluetooth

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Web USB Console - Online Claim & Talk to USB Device

Request a USB device and communicate with it using the Web USB API. See vendor and product IDs. Experimental.

Developer Tools API console device Web USB

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Web HID Explorer - Online List & Read HID Devices

Request HID devices and list them. Read input reports and send output. For custom hardware and controllers.

Developer Tools API devices HID Web HID

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Web Serial Terminal - Online Connect to Microcontroller

Connect to a serial device (Arduino, etc.) via the Web Serial API. Send and receive text. No native app needed.

Developer Tools API microcontroller terminal Web Serial

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Ambient Pressure Sensor Demo - Online Barometer

Read the ambient atmospheric pressure in hPa using the Pressure Sensor API (if available). Real‑time graph.

Developer Tools API barometer pressure sensor

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Linear Acceleration Sensor - Online Motion Visualizer

Visualize real‑time linear acceleration (excluding gravity). Watch the 3D vector graph move as you shake the device.

Developer Tools accelerometer API motion sensor

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Idle Detection API Demo - Online User Activity Monitor

Request permission and detect when the user is idle (away from keyboard). See screen lock state. For native‑like apps.

API API Idle Detection monitor user

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Web OTP API Demo - Online Auto‑Read SMS Codes

Demonstrate how the Web OTP API automatically reads one‑time codes from SMS (mobile). Simulation with a fake SMS input.

API API SMS verification Web OTP

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Font Access API - Online Browse Local Fonts

Enumerate all fonts installed on your device and see a real‑time preview. Useful for design tools. Permission required.

API API Font Access fonts local

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Contact Picker API Demo - Online Select & Read Contacts

Pick a contact from the device’s address book (mobile). Read name, email, and phone. All permission‑based. Privacy safe.

API API Contact Picker contacts mobile

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Wake Lock API Tester - Online Prevent Screen Sleep

Request and release a screen wake lock to keep the device awake. See the lock state in real time. Perfect for recipes or presentations.

Developer Tools API screen sleep Wake Lock

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EyeDropper API - Online Pick Any Screen Color

Use the EyeDropper API to sample a color from anywhere on your screen. Click, select, and copy the hex. No extensions needed.

Color Tool API color EyeDropper picker

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Web Locks API Demo - Online Resource Coordination

Acquire and release locks across tabs. Prevent race conditions in IndexedDB or localStorage. Visual queue and lock state.

API API concurrency demo Web Locks

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Navigation API Playground - Online Single‑Page Router

Intercept and manage navigations without reloading. Test transition handling and URL updates. The future of client‑side routing.

API API Navigation router SPA

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Prioritized Task Scheduler Demo - Online scheduler.postTask()

Schedule tasks with user‑visible, user‑blocking, or background priority. See execution order and delays. Modern web perf.

API API postTask priority scheduler

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Cookie Store API Tester - Online Async Cookie Read/Write

Read, write, and delete cookies using the modern Cookie Store API. Monitor change events. No more document.cookie parsing.

API API async cookies Cookie Store

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File System Access API Demo - Online Open & Save Files

Test the modern File System Access API. Open a file, modify it, and save back to disk. All sandboxed in browser.

API API File System Access open save

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Gamepad API Tester - Online Visual Controller Check

Connect a gamepad and see all button presses and axis movements visually. Check that every input is detected correctly.

Developer Tools API controller gamepad tester

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Vibration API Demo - Online Test Haptic Feedback

Trigger different vibration patterns on mobile devices. Test if your phone supports haptic feedback. Simple demo.

API API haptic mobile Vibration

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Web Notification Tester - Online Permission & Display

Check notification permission, request it, and send a test notification. Verify icon, body, and tag. Debug web push.

API API Notification permission test

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Network Information API Checker - Online Downlink Speed

Display your effective connection type (4g, 3g, etc.) and downlink speed using the Navigator API. Adapt your app accordingly.

Info API connection Network Information speed

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Battery Status API Viewer - Online Check Level

See your device's battery level, charging status, and discharge time using the Battery Status API. Fun utility.

Info API Battery charging level

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Screen Orientation API Tester - Online Lock & Check

Check current screen orientation and test the lock API. Useful for mobile web apps. Demo with code.

API API mobile Screen Orientation test

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Popover API Demo - Online No‑JS Tooltips & Menus

Test the new HTML popover attribute for creating accessible tooltips, menus, and dialogs without JavaScript. Copy code snippets.

Developer Tools API HTML Popover tooltip

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View Transitions API Demo - Online Smooth Page Switch

See the View Transitions API in action. Cross‑fade and morph between two states. Copy the JavaScript starter code.

Developer Tools animation API demo View Transitions

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Clipboard API Tester - Online Read & Write Sandbox

Experiment with the Async Clipboard API: read/write text and images from the clipboard. Verify permissions and see demo code.

API API Clipboard copy paste

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Web Share API Tester - Online Demo & Code

Test the Web Share API by sharing text, links, and files directly from the browser. Check compatibility and see example code.

API API share test Web Share

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API Status Checker - Online Test Endpoint & Response

Enter an API URL and quickly check its HTTP status code and response time. See response headers and body. Browser fetch.

Developer Tools API checker endpoint status