UD5 Toolkit
Robots.txt Generator - Online Create & Validate Robots File
Build a properly formatted robots.txt file with user-agent rules and sitemap location. Validate syntax in real time. Essential for webmasters.
Random User Agent String Generator - Online for Testing
Random User Agent Generator
Generate realistic user agent strings for browser testing, web scraping, and device emulation.
Choose your OS, browser, and device type – or let the tool surprise you. Perfect for QA engineers, developers, and privacy testers.
No user agent matches the selected filters. Try different options.
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Frequently Asked Questions
A user agent (UA) string is a text identifier sent by your browser to websites. It tells the server what browser, operating system, and device you are using, helping sites deliver the right content and layout.
Random UA strings are essential for testing responsive designs, web scraping (to avoid blocking), privacy testing, and verifying that analytics correctly track different devices and browsers.
Yes! The tool draws from a curated pool of modern, real-world UA strings covering popular browsers and operating systems. They reflect actual traffic you'd see in the wild.
Absolutely. Rotating user agents helps avoid rate limiting and detection when scraping responsibly. Combine with other headers and respect robots.txt.
Browser vendors release updates frequently. We keep our pool current with recent Chrome, Firefox, Safari, and Edge versions. For the latest testing, you can always generate fresh ones.
Spoofing means changing your browser's UA string to mimic another device or browser. It's used for testing, privacy, or accessing mobile-only content. This tool helps you create spoofed strings easily.
Yes, 100% free with no registration. Generate as many random user agents as you need for your development and testing workflows.
Robots.txt Validator & Parser - Online Check Syntax
Paste robots.txt content and parse it to check validity, find disallowed paths. Educational SEO tool. Local processing.
Random Encouragement Generator - Online Cheer Up Words
Click for a warm, encouraging sentence to lift your spirits or support a friend. Small positive boost. No repeats.
Speech Utterance Tester - Online Play Word by Word
Hear text spoken word by word with boundary events. See the exact index and character. Advanced TTS dev tool.
Speech Recognition Tester - Online Web Speech API Demo
Test your browser's built‑in speech recognition. Speak and see the transcribed text appear live. Must‑have for voice app devs.
Regex Catastrophic Backtracking Tester - Online Benchmark
Test a regex against long strings and measure execution time. Detect catastrophic backtracking patterns. Visual warning if slow.
Simple Invoice Generator - Online Create & Print Invoices Free
Fill in your details and generate a professional-looking invoice ready to print or save as PDF. No sign-up, all data stays on your device. Great for freelancers.
CUID Generator - Online Collision‑Resistant IDs for Frontend
Generate CUIDs that are optimized for horizontal scaling and collision resistance. Great for client‑side IDs. Pure JavaScript.
Simple Invoice Generator - Online Create & Print Invoices Free
Fill in your details and generate a professional‑looking invoice ready to print or save as PDF. No sign‑up, all data stays on your device.
RSVP Speed Reading Trainer – Online Flash Words
Paste text and set display speed for Rapid Serial Visual Presentation. Train your reading speed.
Spelling Test Practice - Online Audio Dictation & Typing
Hear a word spoken by browser TTS and type the spelling. Choose difficulty or paste your own list. Great for kids. Local only.
Random Life Insight - Online Wise Words
Get a short, thought‑provoking insight or proverb. A moment of reflection. Works offline.
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.
Reaction Time Test - Online Click & Sound
Measure your visual and auditory reaction speed. Average and best times shown. No data collected. Pure Javascript timing.
Speech Length Estimator – Online Words to Minutes
Paste your script and get an approximate speech duration based on slow/average/fast pace. Avoid overtime.
Signal Mirror Practice Simulator – Virtual Aiming Flash
Learn to aim a signal mirror by aligning a virtual finger and target. Simulates the retro‑reflective mesh technique. Practice before you need it.
Event Countdown Timer - Online Days Until Birthday Wedding Vacation
Set any future date and see a live countdown in days, hours, minutes, seconds. Fun animated display. Save multiple countdowns locally.
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.
PX to EM/REM Converter - Online Responsive Unit Calculator
Convert pixel values to em and rem units based on a base font size. Bidirectional. Must‑have for front‑end developers.
HTML Minifier Comparison - Online See Savings Live
Paste HTML and see a before/after comparison of minified output. Check the byte savings. All local.
Virtual Flashlight - Online Color & Strobe Screen
Turn your browser screen into a full‑color flashlight or strobe. Adjust brightness and color. Simple utility.
Speech Timer – Online Practice Presentations with WPM
Paste your speech, set time limit, and practice with a pacing indicator (words per minute). Refine delivery.
Sound Wave Extractor - Online Isolate Vocals or Instrumental
Simple phase cancellation tool: load a stereo track and attempt to remove center‑panned vocals. Not perfect, but fun to experiment.
Ovulation & Fertility Window Calculator - Online Cycle Tracker
Estimate ovulation day and fertility window from last menstrual period. Displays probable conception dates. Informational only; processes locally in browser.
Potty Training Log – Online Record Accidents & Successes
Simple tracker to record potty attempts, successes, accidents. See patterns. Data stays local. Aids in toilet training journey.
DOM Event Inspector - Online See All Event Listeners
Click any element on a demo page and see which events are attached. Visual debugger for event handling.
:focus‑visible Tester - Online Keyboard‑Only Focus Ring
Compare :focus and :focus‑visible styling. See which one applies when using mouse vs. keyboard. Accessible focus management.
Speech to Text Dictation - Online Transcribe Audio & Mic
Use your microphone to dictate text and see it appear live. Also upload an audio file for transcription (limited). All local.
Speech to Text Dictation - Online Transcribe Audio & Mic
Use your microphone to dictate text and see it appear live. Also upload an audio file for basic transcription. All local.
Developmental Milestones Quiz – Online Ages & Stages Fun
Answer questions and see typical milestones for 0-5 years. Educational reference for parents. Not a diagnostic tool.