Dev tools, bench-tested
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185 free tools for formatting, converting, generating and checking. Results update as you type, and nothing you enter is stored.
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Credit Card Number GeneratorValid test cards, made locally→Credit Card ValidatorCheck a card number with the Luhn test→Text RepeaterRepeat any text, emoji too→MongoDB ObjectId ↔ Timestamp ConverterRead the date inside an ObjectId→Internet Speed TestPing, download and upload speed→See all 185 tools →bench / cardnetwork: 0 requests
•••• •••• •••• ••••
CARD HOLDER
YOUR NAME
VALID THRU
MM/YY
A test card. It passes the Luhn check, but it is not a real card. Never use it to buy anything.
Open the full Credit Card Number Generator →
Runs in your browser. Nothing is sent.
From the blog
Long reads for developers, in plain words.
Encoders & Converters
46 tools
Move data between formats, from Base64 to CSV to images.
- ASCII to Decimal ConverterThe ASCII to Decimal Converter is a free online tool from Bytelify that converts characters into their decimal codes. Enter or paste your text to convert ASCII to decimal for programming, debugging, data analysis, learning, and development.
- ASCII to Unicode ConverterDecode \uXXXX ASCII-safe escape sequences back to Unicode text, live as you type.
- Base64 Decode Online (Base64 Decoder)Decode Base64 to readable text with Bytelify's free online Base64 decoder and Base64 to text converter. Paste a Base64 string and the decoded result appears instantly.
- Base64 EncoderEncode text to Base64 instantly, live as you type, Unicode-safe.
- BCD to Decimal ConverterConvert Binary-Coded Decimal to decimal, live as you type.
- Binary to Decimal ConverterConvert binary numbers to decimal instantly, with no size limit.
- CSV to Excel File ConverterConvert CSV to a downloadable Excel file, live preview, entirely in your browser.
- CSV to JSON ConverterConvert CSV to JSON instantly, live as you type, using the first row as field names.
- CSV to TXT ConverterConvert CSV to plain delimited text (tab, space, or pipe), live as you type.
- Decimal to ASCII ConverterConvert decimal character codes back to text, live as you type.
- Decimal to Binary ConverterConvert decimal numbers to binary instantly, with no size limit.
- Decimal to Gray Code ConverterConvert decimal to Gray code (binary), live as you type.
- Decimal to Hexadecimal ConverterConvert decimal numbers to hexadecimal instantly, with no size limit.
- Decimal to Octal ConverterConvert decimal numbers to octal instantly, with no size limit.
- Gray Code to Decimal ConverterConvert Gray code (binary) to decimal, live as you type.
- Hex to Text Converter (Hex to ASCII)Convert hexadecimal values into readable text. Paste your hex bytes and read the decoded characters as you type, for programming, debugging and development, all in your browser.
- Hexadecimal to Binary ConverterConvert hexadecimal numbers to binary instantly, with no size limit.
- HTML Entities to Text ConverterDecode HTML entities back to plain text, live as you type, in either direction.
- HTML EscapeEscape text for safe use inside HTML, live as you type, in either direction.
- HTML UnescapeDecode HTML entities back to plain text, live as you type, in either direction.
- IDN DecodeDecode a Punycode domain back to Unicode, live as you type.
- IDN EncodeEncode an internationalized domain name to Punycode, live as you type.
- IP to HexConvert an IPv4 address to its hexadecimal representation, live as you type.
- JavaScript EscapeEscape text for use inside a JS/JSON string literal, live as you type, in either direction.
- JSON to CSV ConverterConvert a JSON array of objects to CSV instantly, live as you type.
- JSON to TXT ConverterFlatten JSON into a plain key: value listing, live as you type.
- JSON to TypeScriptInfer TypeScript interfaces from a sample JSON value, live as you type.
- JSON to XML ConverterConvert JSON to XML instantly, live as you type.
- JSON to YAML ConverterConvert JSON to YAML instantly, live as you type.
- MongoDB ObjectId ↔ Timestamp ConverterBytelify's MongoDB Timestamp Converter is a free online tool that extracts the timestamp embedded in a MongoDB ObjectId and converts a date and time into a comparison-ready ObjectId.
- Octal to Binary ConverterConvert octal numbers to binary instantly, with no size limit.
- Octal to Decimal ConverterConvert octal numbers to decimal instantly, with no size limit.
- ROT13 Encoder/DecoderDecode or encode ROT13 text with Bytelify's free online ROT13 decoder and encoder. Type or paste any text and every letter shifts 13 places through the alphabet as you type.
- SQL to CSV ConverterConvert SQL INSERT statements to CSV, live as you type.
- SQL to JSON ConverterConvert SQL INSERT statements to JSON, live as you type.
- Text to CSV ConverterConvert delimited text to CSV, live as you type.
- Convert Text to HTML EntitiesEncode text to HTML entities, live as you type, in either direction.
- Convert TXT to CSVConvert delimited plain text into properly quoted CSV, live as you type, download or copy the result.
- Unicode to ASCII ConverterEncode Unicode text to \uXXXX ASCII-safe escape sequences, live as you type.
- Unix Timestamp ConverterConvert between a Unix timestamp and a readable date, live as you type.
- URL DecoderDecode percent-encoded URLs and query strings instantly, live as you type.
- URL EncoderPercent-encode text for safe use in a URL or query string, live as you type.
- UTF8 DecodeDecode raw UTF-8 bytes back to text, live as you type.
- UTF8 EncodeEncode text to its raw UTF-8 bytes, live as you type, shown as hex or decimal.
- XML EscapeEscape the five reserved XML characters, live as you type, in either direction.
- XML to JSON ConverterConvert XML to JSON instantly, live as you type.
Formatters & Validators
39 tools
Format, minify, compare and validate code and data, from JSON to SQL.
- Code Compare ToolCompare two blocks of code line by line and see exactly what changed, in any language.
- Credit Card ValidatorThe Credit Card Validator is a free online tool from Bytelify that checks credit card numbers using the Luhn checksum and identifies the card network. Use it for development, testing, and payment-form validation without sending card data to a server.
- CSS MinifyStrip comments and unnecessary whitespace from CSS, live as you type.
- CSS PrettifyFormat and indent minified CSS into clean, readable code, live as you type.
- CSS to LESSConvert flat CSS into nested LESS, live as you type.
- CSS to SASSConvert flat CSS into nested SCSS, live as you type.
- CSS ValidatorCheck CSS for rules that fail to parse, live as you type.
- Excel CompareUpload two .xlsx files to see every cell that differs between them, highlighted in a single spreadsheet-style grid.
- GraphQL FormatterFormat and indent GraphQL queries into clean, readable syntax, live as you type.
- HTML MinifyStrip comments and unnecessary whitespace from HTML, live as you type.
- HTML PrettifierFormat and indent messy HTML into clean, readable markup, live as you type.
- HTML TesterTest HTML for unclosed or mismatched tags with a live, sandboxed preview.
- HTML to BBCode ConverterConvert HTML to BBCode, live as you type.
- HTML to Markdown ConverterConvert HTML to Markdown instantly, live as you type.
- HTML ValidatorCheck that HTML tags are properly opened and closed, live as you type.
- JS Minify ToolMinify JavaScript with real variable renaming and dead-code removal, live as you type.
- Javascript Regex TesterTest a regular expression against a string with live match highlighting.
- JavaScript TesterRun JavaScript and see its console output, in a fully sandboxed iframe.
- JavaScript ValidatorCheck JavaScript for syntax errors, live as you type, using your browser's own engine.
- JavaScript ObfuscatorObfuscate JavaScript to make it harder to read, using real AST-based transformation.
- JSON CompareCompare two JSON documents line by line and see exactly what changed.
- JSON Minify ToolMinify JSON by stripping all whitespace, live as you type.
- JSON Prettifier ToolFormat, validate, and minify JSON live as you type, with the exact parser error if it's invalid.
- JSON ValidatorCheck JSON for syntax errors, live as you type, with the parser's exact error message.
- Markdown FormatterFormat Markdown with consistent spacing and list markers, live as you type.
- Markdown to HTML ConverterRender Markdown to HTML instantly, live as you type.
- PAN Card ValidatorCheck that a PAN number has the right format and see what each part means, from the holder type to the check letter.
- PHP FormatterRescale your PHP code's indentation to a consistent width, live as you type.
- Python FormatterRescale your Python code's indentation to a consistent width, live as you type.
- SCSS to CSS ConverterFlatten nested SCSS selectors into plain CSS, live as you type.
- SQL Formatter & BeautifierFormat and indent SQL queries into clean, readable syntax, live as you type, across multiple dialects.
- SQL MinifyStrip comments and collapse whitespace in SQL to a single line, live as you type.
- Difference Checker (String)Highlight the character-level difference between two strings, live as you type.
- Text CompareCompare two blocks of text line by line and see exactly what was added, removed, or changed.
- TypeScript FormatterFormat and beautify TypeScript with Prettier, live as you type.
- XML CompareCompare two XML documents line by line and see exactly what changed.
- XML MinifierStrip comments and unnecessary whitespace from XML, live as you type.
- XML PrettifyFormat and indent minified XML into clean, readable markup, live as you type.
- YAML Formatter & BeautifierFormat YAML with consistent indentation, live as you type.
Random Generators
27 tools
Make test data, codes and placeholders on demand.
- API Key GeneratorGenerate random API-key-shaped strings for placeholder/test use.
- Barcode GeneratorGenerate a scannable barcode in CODE128, EAN13, UPC, and more formats, live as you type.
- Credit Card Number GeneratorThe Credit Card Number Generator is a free online tool from Bytelify that generates dummy credit card numbers for development, testing, and QA. Create credit card test data for payment forms, checkout flows, and validation without using real card information.
- HTML Code GeneratorBuild a starter HTML5 document by toggling common options, live.
- Random JSON Data GeneratorDefine fields and generate realistic-looking fake JSON test data.
- Lorem Ipsum Text GeneratorGenerate classic Lorem Ipsum placeholder paragraphs for mockups and layout testing.
- Placeholder Image GeneratorThe Placeholder Image Generator is a free online tool from Bytelify for creating an image placeholder with custom dimensions, colors, and PNG output. Generate placeholder images for websites, mockups, wireframes, UI designs, and development projects without using final image assets.
- QR Code GeneratorTurn any text or URL into a scannable QR code, live as you type, free to download.
- Random Address GeneratorGenerate plausible-looking but entirely fake US-style addresses for test data.
- Random Letter and Character GeneratorGenerate random individual characters (letters, numbers, and symbols) with configurable character sets.
- Random Color GeneratorGenerate random hex colors with a live swatch preview and one-click copy.
- Random CSV GeneratorDefine fields and generate realistic-looking fake CSV test data.
- Random Date GeneratorGenerate random dates within a chosen range, for test data or sample datasets.
- Random Decimal Number GeneratorGenerate random decimal numbers within a range, with a chosen number of decimal places.
- Random GUID GeneratorGenerate RFC 4122 v4 GUIDs/UUIDs instantly.
- Random IP Generator OnlineBytelify's Random IP Generator is a free online tool that generates random IPv4-format addresses for development, testing, and sample data.
- Random Number GeneratorGenerate random numbers in any range, one or thousands at a time, instantly in your browser.
- Random Paragraph GeneratorGenerate random filler paragraphs made of grammatical sentences, for mockups and layout testing.
- Random Password GeneratorGenerate a strong, random password instantly, with control over length and character types.
- Random Sentence GeneratorGenerate random, grammatically correct sentences for writing prompts or filler text.
- Random String GeneratorGenerate random strings of any length from uppercase letters, lowercase letters, numbers and symbols, for test data, sample IDs and placeholder values.
- Random Text from RegExGenerate random strings that match a regular expression pattern, live as you type.
- Random Clock Time GeneratorGenerate random 24-hour clock times (HH:MM:SS).
- Random Username GeneratorGenerate random, available-sounding usernames by combining an adjective, a noun, and a number.
- Random Word GeneratorGenerate random English words for games, writing prompts, or filler content.
- Random XML GeneratorGenerate a small, valid, randomly-shaped XML document with nested elements and attributes.
- UPI QR Code GeneratorMake a UPI QR code from your UPI ID. Add a name, an optional amount and a note, pick colours and a logo, then download a PNG or SVG.
Text Tools
18 tools
Clean up, count, repeat and reshape text.
- Character Count ToolCount characters, words, sentences, and more, live as you type.
- Find and Replace StringFind and replace text, with optional case sensitivity and regex, live as you type.
- Line Count ToolCount lines, words, characters, and more, live as you type.
- Morse Code TranslatorTranslate text to Morse code and back, live as you type, with an optional audio playback.
- Phone Number Extractor ToolExtract phone numbers from a block of text, live as you type.
- Remove SpacesRemove extra spaces, trim lines, or strip all whitespace, live as you type.
- Reverse Text GeneratorReverse any text instantly, live as you type, Unicode-safe.
- Sentence Count ToolCount sentences, words, characters, and more, live as you type.
- Shuffle LettersRandomly reorder every character in your text, live as you type.
- Shuffle Text LinesRandomly reorder the lines in your text, live as you edit.
- Sort Words AlphabeticallySort a list of words or lines alphabetically, live as you type, with case and duplicate options.
- Sorting ListSort a list alphabetically, numerically, by length, or shuffle it randomly.
- Strip HTMLRemove all HTML tags and get the plain text, live as you type.
- Text to Lowercase ConverterConvert text to lowercase instantly, live as you type, Unicode-safe.
- Text RepeaterThe Text Repeater is a free online tool from Bytelify that repeats any text as many times as you need. Enter your text, choose a repeat count and what goes between the repeats, then copy or download the result instantly.
- Text to One LineJoin multi-line text into a single line, live as you type.
- Text to Uppercase ConverterConvert text to UPPERCASE instantly, live as you type, Unicode-safe.
- Word Count ToolCount words, characters, sentences, and paragraphs live as you type, plus an estimated reading time.
Number & Color Tools
16 tools
Convert number bases and color formats, and do quick maths.
- Bitwise CalculatorCompute AND, OR, XOR, NOT, and bit shifts on integers, live as you type.
- CMYK to Hex Converter: CMYK to Hex CodeConvert C, M, Y, K values to a hex color code, live as you type.
- CMYK to RGB ConverterConvert CMYK print colors to RGB screen values, with a live swatch.
- Color InverterInvert any color and see the original and inverted swatches side by side, copy either hex code.
- Color PickerPick a color and get its HEX, RGB, and HSL values instantly, copy any of them with one click.
- Fibonacci CalculatorGenerate the Fibonacci sequence up to any number of terms, live as you type, with no precision loss.
- GST CalculatorAdd GST to a price or take it out of a total. Pick the rate and see the CGST, SGST or IGST split, with every amount ready to copy.
- Hex to CMYK Converter: Hex Color Code to CMYKConvert a hex color code to CMYK values for print, live as you type.
- Hex to RGB ConverterBytelify's Hex to RGB Converter is a free online tool that converts hexadecimal color codes into RGB values instantly. Enter a six-digit hex color code to see its red, green, and blue components along with a live color preview.
- Number to Words ConverterConvert number to words live as you type. Spells out whole numbers and decimals in English, with currency, Indian lakh and crore, ordinals and up to 36 digits.
- RGB to CMYK Converter: RGB Color to CMYKFree RGB to CMYK converter: turn an RGB color into CMYK print values, live as you type.
- RGB to Hex ConverterBytelify's RGB to HEX Converter is a free online tool that converts RGB color values into hexadecimal color codes instantly. Enter the red, green, and blue values to get the equivalent six-digit HEX code and preview the color in real time.
- Rounding CalculatorRound a number up, down, or to the nearest value, to any number of decimal places, live as you type.
- Sort NumbersSort a list of numbers ascending or descending, live as you type.
- Words to Numbers ConverterParse English number words like "two hundred and fifty three" back into a numeric value, live as you type.
- XOR CalculatorXOR two values byte-for-byte, live as you type, in text or hex.
Browser & System Info
15 tools
See what your browser, device and connection tell a website.
- Am I Using Tor?Check whether your current IP address matches a known Tor exit node, using the Tor Project's own published list.
- Internet Speed TestThe Internet Speed Test is a free online tool from Bytelify that measures your connection's ping, download speed, and upload speed. Run a quick browser-based test against the Cloudflare server nearest you, with no account, app, or browser extension.
- What Is My BrowserSee your browser, OS, and version at a glance, along with screen size and language settings.
- What Is My ISP? Find My ISP and IP AddressFind my ISP: see your Internet Service Provider, public IP address, ASN, and approximate location, detected instantly from your connection.
- What Is My Local IP AddressAttempts to detect your local (private network) IP address using your browser's WebRTC APIs, with an honest result either way.
- What Is My User AgentSee your browser's exact user agent string, plus a best-effort guess at your browser and OS.
- What Operating System Do I HaveSee your operating system and version, read from your user agent string.
- What Version of Android Do I HaveSee which Android version your browser reports, read from your user agent.
- What Version of Chrome Do I HaveSee your Chrome version, read from your user agent string.
- What Version of Firefox Do I HaveSee which Firefox version your browser reports, read from your user agent.
- What Version of iOS Do I HaveSee which iOS version your browser reports, read from your user agent.
- What Version of macOS Do I HaveSee which macOS version your browser reports, read from your user agent.
- What Version of Safari Do I HaveSee which Safari version your browser reports, read from your user agent.
- What Version of Windows Do I HaveSee which version of Windows your browser reports, read from your user agent.
- What's My Browser Size?Check your browser size, screen resolution, browser, operating system and user agent, all live in your browser.
Developer Utilities
9 tools
Small helpers for everyday development: JWT, cron, sitemaps and more.
- Bcrypt GeneratorGenerate and verify bcrypt password hashes, entirely in your browser.
- Crontab GeneratorBuild a cron expression field by field, with a plain-English description and common presets.
- GitHub README GeneratorFill in your project details and get a clean README.md with a live preview. Copy it or download it, then drop it in your repository.
- HTML ViewerPaste HTML and see it rendered live, in a sandboxed preview that never executes scripts.
- Image ResizerResize an image to exact dimensions, entirely in your browser.
- JWT DecoderDecode a JSON Web Token's header and payload instantly, entirely in your browser.
- Rotate ImageRotate an image 90°, 180°, or 270° and download the result, entirely in your browser.
- Sitemap FinderEnter a domain to pull every URL listed in its sitemap.xml, falling back to the Sitemap: line in robots.txt if needed.
- SVG ViewerPaste SVG markup and see it rendered live, in your browser.
Unit Converters
7 tools
Convert temperature, time, length and pixels.
- Celsius to Fahrenheit ConverterConvert Celsius to Fahrenheit, or Fahrenheit to Celsius, live as you type in either field.
- Hours to Seconds ConverterConvert hours to seconds, live as you type, in either direction.
- KM to Miles ConverterConvert kilometers to miles, or miles to kilometers, live as you type in either field.
- Miles to KM ConverterBytelify's Miles to KM Converter is a free online tool that converts miles to kilometers and kilometers to miles instantly. Enter a distance in either field to see the converted result as you type.
- PX to Rem ConverterConvert pixel values to rem units, live as you type, based on the standard 16px root font size.
- Rem to PX ConverterConvert rem units to pixel values, live as you type, based on the standard 16px root font size.
- Time CalculatorAdd, subtract, multiply, or divide durations, or find the time between two dates.
Nothing leaves this tab.
Almost every tool here runs on your device. Paste a token, a key or a customer record and it is never uploaded, stored or logged. The 5 tools that do need the network say so on their own page, and name who they talk to.
Social & Messaging
8 tools
Chat links, QR codes and text formatters for WhatsApp, Telegram, LinkedIn, Instagram and more.