World Flag Quiz - Online Guess the Country by Flag
Identify countries from their flags. Multiple difficulty levels and regions. Track your high score. Educational geography game. Works offline.
UD5 Toolkit
Discover detailed information about any country — instantly.
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Identify countries from their flags. Multiple difficulty levels and regions. Track your high score. Educational geography game. Works offline.
Random world flags shown; pick the correct country name from four choices. Score and streak. Learn geography.
Test yourself on international calling codes. Random country, type the code. Or reverse. Perfect for travelers.
Interactive soprano recorder chart showing which holes to cover for each note. Switch between baroque and German fingering.
Add Vietnamese diacritics to plain text by selecting tones. Remove them from text. For language learners.
Click on a fold technique (spiral, crumple) and see a predicted color pattern. Print folding guide.
Eliminate duplicate lines from text instantly. Keep only unique lines or see which lines were removed. Handy for cleaning email lists and raw data.
Generate a QR code from any text, URL, or contact details. Save as PNG, SVG, or copy to clipboard. All local.
Create QR codes with custom colors, gradients, and an embedded logo. Download as high-quality PNG/SVG. Fully local generation.
Create high-quality QR codes for URLs, text, Wi-Fi, and contact info. Customize colors and size. Download as PNG/SVG. No data leaves your device.
Generate a QR code with a custom icon or logo in the center. Choose error correction level. Download as high‑res PNG.
Create binaural beats by setting base frequency and beat frequency. Use headphones. For relaxation or focus. Web Audio API.
Generate a self‑signed X.509 certificate and private key for local development. All created in your browser. No server involved.
Test your knowledge of the NATO phonetic alphabet. Timed quiz with letter‑to‑code and code‑to‑letter modes.
Paste text and instantly see every character's decimal and hex ASCII/Unicode code point. Supports emojis and symbols.
Apply a classic Caesar shift cipher with any key. Encrypt or decrypt text instantly. Brute force option included.
Convert any text to proper sentence case. Capitalize the first letter after every period, question mark, or exclamation.
Interactive scale showing dB levels of everyday sounds with playable samples. Hearing safety.
Browse the built‑in styles that browsers apply to HTML elements. Understand why your page looks different. Static reference.
Search by country or city to find the capital. Full offline list. Useful for homework or travel planning. Static data.
See a flag and pick the country among four choices. Timed rounds with score. Perfect for geography buffs. Local data.
Search and browse a comprehensive table of SI units and common imperial conversions. For students and engineers.
Search by country or currency name to find its symbol and code. Quick static reference for international business.
A clean, printable Morse code chart with letters, numbers, and common punctuation. Learn and decode easily. Static.
Search for any file extension to see its full name, MIME type, and description. Covers thousands of entries. Static data.
An interactive reference for regular expression tokens. Click a token to see its explanation and example. Learn regex faster.
Searchable grid of all named HTML character entities with previews. Click to copy &, <, © etc. For web devs.
Search a library of famous company brand colors with hex codes. Copy any color instantly. For designers and marketers.
A visual guide to common copy‑editing and proofreading symbols. Click a mark to see its meaning. For writers.
Search by MIME or file extension to see the corresponding type. Helpful when configuring web servers. Static.