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Convolution Reverb Demo - Online Impulse Response Player

Apply realistic reverbs (cathedral, hall, room) to any audio using pre‑loaded impulse responses. Hear the difference instantly.

Multimedia convolution impulse response reverb web audio

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Simple Page Speed Tester - Online Core Web Vitals Emulator

Enter a URL and get a quick simulation of First Contentful Paint, LCP, and CLS using browser metrics. Lightweight alternative.

Developer Tools CLS LCP page speed Web Vitals

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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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Core Web Vitals Simulator - Online Learn How to Improve LCP/INP/CLS

Adjust page characteristics (image size, server delay, layout shift) and see the simulated Core Web Vitals scores. Understand what impacts performance.

Developer Tools LCP performance simulator Web Vitals

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Reduced Motion Demo - Online Prefers‑Reduced‑Motion Switcher

Toggle between full and reduced motion on a live animated page. See how to design for vestibular disorders. Educational.

Accessibility a11y animation demo reduced motion

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ASCII Video Player - Online Convert Webcam to Text Art Live

Turn your webcam feed into real‑time ASCII art. Adjust density and character set. Fun for streams and demos. No upload.

Entertainment art ASCII video webcam

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forced‑colors Mode Tester - Online Windows High Contrast

Simulate forced‑colors mode and see how your site looks. Adjust CSS system colors. Make your design accessible.

Accessibility a11y forced‑colors high contrast test

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UI Animation Timing Demo - Online Easing Presets

Compare all CSS easing presets side by side on a bouncing ball. See which curve fits your UI animation.

Design animation demo easing UI

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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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Video Subtitle Burner - Online Hardcode SRT into Video

Merge an SRT subtitle file onto a video directly in the browser. Preview and download the resulting video. All local.

Editor burner hardcode subtitle video

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Brotli Compression Level Tester - Online Optimal Setting

Compress text with Brotli at different quality levels. See size reduction and time. Find the sweet spot for your static assets.

Developer Tools Brotli compression performance test

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GIF Playback Speed Changer - Online Slow Down or Speed Up

Load an animated GIF and adjust its frame delay to make it slower or faster. Download the modified GIF. All local.

Editor animated change GIF speed

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prefers‑reduced‑motion Tester - Online A11y Check

Simulate reduced motion preference and test your animations. Copy the media query snippet. Keep your users safe.

Accessibility a11y media query prefers‑reduced‑motion test

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Base32 Encoder & Decoder - Online Base32 Converter

Encode or decode text using Base32 scheme. Ideal for legacy systems and data obfuscation. Works completely offline in your browser for maximum security.

Developer Tools Base32 converter decoder encoder

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Online Video Reverser - Play & Save Backwards

Reverse any short video clip and download the backward version. Fun for creative effects. Browser‑based.

Editor backwards play reverse video

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Base64 Encoder & Decoder - Online Base64 Converter

Convert text and files to Base64 or decode Base64 back to original content. Processed locally with no server upload, ensuring complete data security.

Developer Tools Base64 converter decoder encoder

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Beat Sync Tester - Online Tap Tempo & BPM Counter

Tap any key to the beat and get the BPM (beats per minute). Useful for DJs, musicians, and running. Simple and accurate.

Multimedia BPM music tap tempo

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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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Language Flashcard Randomizer - Online Vocabulary Trainer

Paste word pairs (or load pre-made sets) and practice with randomized flashcards. Flip to reveal translation, mark as known/unknown. Local data, no login.

Education flashcard language study vocabulary

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TCP State Machine Visualizer - Online Animated Diagram

Click through the TCP connection states (LISTEN, SYN_SENT, ESTABLISHED…) and see the animated transitions. Networking education.

Educational animated diagram state machine TCP

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Online SRT Subtitle Shifter - Adjust Timing & Sync

Load an SRT file and shift all timestamps forward or backward by milliseconds or seconds. Fix out-of-sync subtitles instantly. Download corrected file.

Editor shift SRT subtitle sync

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QR Code vCard Maker - Online Contact Card Code

Create a QR code that contains your full vCard contact information. Scan to save directly to a phone. No data leaves browser.

Business contact generator QR vCard

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Live Web Vitals Monitor - Online Real‑Time LCP, INP, CLS

Patch the PerformanceObserver and show your page’s Core Web Vitals as you browse. See real‑time scores and suggestions.

Developer Tools INP LCP real‑time Web Vitals

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Braille to Text Converter - Online Decode Dot Patterns

Enter Braille dot numbers (1‑6) or paste Unicode Braille to decode into English text. Companion to text‑to‑Braille.

Accessibility accessibility Braille decode text

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Data Structure Visualizer - Online Array, Stack, Queue

Add, remove, push, pop items and watch the data structure change visually. Supports arrays, stacks, and queues. For CS students.

Developer Tools array data structures stack visualizer

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File MIME Type & Magic Bytes Detector - Online

Drop a file to see its MIME type and the first few magic bytes (hex and ASCII). No upload, works instantly.

Developer Tools detector file magic bytes MIME

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content‑visibility: auto Tester - Online Render Deferral

Apply content‑visibility: auto to off‑screen sections and see the rendering cost drop. Demos for infinite scroll optimization.

Developer Tools content‑visibility CSS performance rendering

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Caffeine Half‑Life Tracker - Online Blood Level Visualizer

Visualize how caffeine decays in your body over time. Enter intake amount and see remaining caffeine at bedtime to optimize sleep. Uses standard 5-hour half-life.

Health & Fitness caffeine coffee half-life sleep tracker

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WASM Audio Decoder - Online Play FLAC/Opus Locally

Decode FLAC, Opus, or OGG audio files in the browser using compiled WASM libraries. Play instantly without server uploads. Keep audio private.

Decoder audio decoder FLAC WASM

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Unicode Normalization Tester - Online See NFC vs NFD

Paste two strings that look the same and see if they differ after normalization. Debug invisible encoding bugs.

Debugging NFC normalizer test Unicode