~/tools $
Free online tools_
65 utilities for developers, designers and everyone — everything runs in your browser, no sign-up, your data never leaves your device.
# Generators · 8
QR Code GeneratorGenerate free QR codes from links, text or Wi-Fi credentials. Customize size, colors, error correction and download as PNG.Password GeneratorGenerate strong, secure random passwords in your browser (Web Crypto). Customize length and character sets.UUID GeneratorGenerate UUID v4 (random) or v7 (time-sortable, RFC 9562) in bulk, right in your browser.Random Number GeneratorGenerate random numbers in any range — single or multiple, with duplicate control. Uses Web Crypto for fair results.Fake Data GeneratorGenerate mock data (names, emails, addresses, companies…) in Vietnamese or English for testing — export JSON/CSV.Wheel of NamesEnter a list of names and spin the wheel to pick a random winner — raffles, team splits, giveaways.Duck RaceEvery name becomes a racing duck — hit start and see which one finishes first. A more fun random picker than the wheel, great for group draws.Lorem Ipsum GeneratorGenerate placeholder text (Lorem Ipsum) by paragraph, sentence or word to fill mockups and drafts. Includes a Vietnamese variant.
# Converters · 12
Base64 ConverterEncode and decode Base64 for text (full UTF-8 support) and files. Everything is processed in your browser.URL Encoder & DecoderEncode and decode URLs (percent-encoding) with UTF-8 support — handles special characters in links and query strings.Unix Time ConverterConvert Unix timestamps to human-readable dates (multiple timezones) and back. Auto-detects seconds / milliseconds, with a live epoch clock.Color ConverterConvert colors between HEX, RGB, HSL, HSV, CMYK, HWB, LAB and LCH — with tint/shade scales and the closest color name.CSV ↔ JSON / ExcelConvert between CSV, JSON and Excel (.xlsx) with a preview table — processed entirely in your browser, nothing is uploaded.CSV ToolsImport, create & edit CSV — table or text view, query, merge, convert, clean and stats.Currency ConverterConvert between 160+ currencies with daily-updated rates, including VND. Open, free rate source.Crypto ConverterConvert cryptocurrencies (Bitcoin, Ethereum, USDT…) between each other or to fiat (USD, VND, EUR…) at real-time prices from CoinGecko.Gold Price ConverterConvert world gold (XAU) and Vietnamese gold types (SJC, 9999 rings, 24K/22K/18K…) across lượng, chỉ, gram and ounce — prices updated in real time.Curl to CodeConvert cURL commands into JavaScript, Python, PHP, Go, Java, C#, Ruby, Rust, Swift, Kotlin… in one click.Number to WordsConvert numbers into Vietnamese and English words — for invoices, contracts and accounting. Supports negatives, decimals and currency formatting.YAML ↔ JSON ConverterConvert between YAML and JSON right in your browser — validate syntax, preserve key order and download the result. Great for config files.
# Dev tools · 9
JSON EditorEdit, validate, format, minify and sort JSON keys; view as a collapsible tree, convert to YAML and back — with line numbers, drag-and-drop files and exact line/column errors.JWT DebuggerDecode JWT header and payload and verify signatures right in your browser — the token never leaves your device.Code BeautifierFormat & beautify many languages: JavaScript, TypeScript, JSON, CSS, SCSS, LESS, HTML, XML, SQL, YAML — adjustable indentation, processed in your browser.Code ObfuscatorObfuscate code to make it hard to reverse-read, entirely in your browser: JavaScript (javascript-obfuscator) plus PHP, Python, Ruby and Shell (base64 + eval packing).Crontab ExplainerPaste a cron expression and get a plain-language explanation with the next 5 run times.Hash TextCompute MD5, SHA-1, SHA-256, SHA-384, SHA-512 and HMAC in your browser with Web Crypto — data never leaves your device.Regex TesterTest regular expressions live: highlight matches, inspect capture groups and try replacements — all in your browser.Number Base ConverterConvert numbers between binary, octal, decimal and hexadecimal (plus a custom base 2–36). Handles very large numbers and shows bit details.XML EditorEdit, format, minify and validate XML — and convert it to JSON in one click. Runs entirely in your browser, nothing is uploaded.
# Text · 7
Word CounterCount words, characters, sentences and paragraphs — with reading time, speaking time and keyword density. Vietnamese-aware.String ToolsTransform, encode, hash, diff, count, line ops, replace, stats & generators — all in one.Text Diff / CompareCompare two text blocks by line, word or character — additions and deletions highlighted in color.Markdown EditorWrite Markdown with a formatting toolbar (no syntax to memorize), live preview (GFM: tables, code, checkboxes), keyboard shortcuts, and export to .md / .html.Typing Speed TestMeasure your typing speed (WPM) and accuracy in 60 seconds — common Vietnamese or English words.Slugify (Vietnamese)Turn accented Vietnamese titles into clean, ASCII, SEO-friendly URL slugs. Processes multiple lines at once, right in your browser.Case ConverterConvert text into every casing style: UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, CONSTANT_CASE… Click to copy each one.
# Calculators · 8
CalculatorCasio-style scientific calculator: arithmetic, powers, roots, trigonometry (DEG/RAD), logs, factorial, %, M memory, Ans, history and keyboard support.BMI CalculatorCalculate your Body Mass Index in metric or imperial units, with category breakdown and simple tips.Percentage CalculatorSolve any percentage problem fast: X% of Y, X as a percent of Y, percentage increase and decrease.Aspect Ratio CalculatorCalculate dimensions for any aspect ratio — enter one side and the other is computed. Presets for 16:9, 4:3, 1:1 and more.Date CalculatorCalculate the gap between two dates (years, months, days, hours) or add and subtract time from any date.Unit ConverterConvert units of measurement: length, mass, temperature, area, volume, data, speed and time — instantly.Vietnam Income TaxCalculate Vietnamese personal income tax and convert gross ↔ net salary — after social/health/unemployment insurance and personal & dependent deductions, using the current progressive scale.Loan CalculatorCompute the monthly payment, total interest and amortization schedule with two methods: equal installments (annuity) and reducing balance.
# Time · 4
ChronometerPrecise stopwatch with centisecond display, lap recording and keyboard controls.Pomodoro TimerStay focused with 25-minute work intervals using the Pomodoro Technique — with notifications, a chime and auto-advance.Sleep CalculatorFind the best bedtime or wake-up time based on 90-minute sleep cycles — wake up refreshed, not groggy.Lunar Calendar ConverterConvert between solar (Gregorian) and lunar (Vietnamese) dates with the Can Chi sexagenary names for year and day — computed for GMT+7, in your browser.
# Image & color · 7
QR Code ReaderScan QR codes from your camera or an uploaded image — decoded in your browser, nothing is uploaded.Image Palette ExtractorExtract the dominant color palette from any image.Color Contrast CheckerCheck text/background contrast ratios against WCAG standards (AA, AAA) — make sure your colors are readable for everyone.Screenshot BeautifierAdd gradient backgrounds, a macOS frame, rounded corners and shadows to screenshots — export PNG or copy to clipboard.Image CompressorCompress JPEG/WebP images to shrink file size while keeping quality — tune the compression level and max width. Processed entirely in your browser, no upload.Image Format ConverterConvert images between PNG, JPG and WebP right in your browser — no upload, your files stay private.Photo BoothShoot a 4-photo booth strip with your webcam, countdown and filters included — download the keepsake strip.
# Web & marketing · 10
What is my IP?See your public IP address with network details: ISP, location, timezone, ASN.Campaign URL BuilderAdd UTM parameters to links to measure campaigns in Google Analytics — utm_source, utm_medium, utm_campaign…Meta Tag GeneratorGenerate SEO, Open Graph and Twitter Card meta tags with live Google result and Facebook share previews.Scrollbar CustomizerDesign a custom scrollbar with live preview — exports CSS for both Chrome/Safari (webkit) and Firefox.CSS Gradient GeneratorBuild CSS gradients (linear, radial, conic) with a visual editor — drag color stops, tweak the angle and copy ready-to-use CSS.CSS Box Shadow GeneratorCreate multi-layer CSS box-shadows with a live preview — adjust offset, blur, spread, color, opacity and inset, then copy the CSS.Email Signature GeneratorCreate professional HTML email signatures for Gmail, Outlook and Apple Mail — copy and paste with formatting intact.CV BuilderBuild a professional, ATS-friendly CV with a live A4 preview — export to PDF via the print dialog, drafts auto-saved locally.Network Speed TestTest your internet download, upload speeds, and ping.Poll MakerCreate a quick poll with your own options and share one link — everyone votes and watches the results update live. No sign-up.