Developer Tools
Encoders, formatters and generators for everyday dev work.
UUID Generator
Generate random v4 UUIDs (GUIDs) in bulk and copy them with one click. Free, instant and fully in-browser using the secure crypto API.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to text instantly. Free, private, in-browser — supports full Unicode (UTF-8).
JSON Formatter & Validator
Format, beautify, minify and validate JSON instantly. Free, private, in-browser JSON formatter with clear error messages.
QR Code Generator
Generate a QR code from any text, link, email or phone number and download it as a PNG. Free, instant and fully in-browser.
Password Generator
Generate strong, random passwords with custom length and character sets, using the secure Web Crypto API. Free and fully private.
Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal instantly. Free in-browser hex-to-decimal and base converter.
Color Converter (HEX / RGB / HSL)
Convert colors between HEX, RGB and HSL, with a live colour picker and preview. Free, instant in-browser color converter.
Unix Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and back, in local time and UTC. Free, instant, in-browser.
Hash Generator (SHA-256)
Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text using the secure Web Crypto API. Free, instant, in-browser.
JWT Decoder
Decode a JSON Web Token (JWT) to read its header and payload instantly. Free, private, in-browser — no token is uploaded.
URL Encode / Decode
Encode text for safe use in URLs or decode percent-encoded URLs back to text. Free, instant, in-browser URL encoder/decoder.
HTML Encode / Decode
Encode HTML special characters to entities or decode entities back to text. Free, instant, in-browser HTML entity encoder/decoder.
JSON to CSV
Convert a JSON array of objects into CSV you can open in Excel or Sheets. Free, instant, in-browser JSON to CSV converter.
CSV to JSON
Convert CSV data into a JSON array of objects using the header row as keys. Free, instant, in-browser CSV to JSON converter.
Text Diff Checker
Compare two blocks of text and see added and removed lines highlighted. Free, instant, in-browser diff checker.
Text to Binary Converter
Convert text to binary and binary back to text (UTF-8). Free, instant, in-browser text-to-binary converter.
Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers. Free, instant, in-browser converter (1–3999).
Random Number Generator
Generate random numbers in any range, with optional uniqueness, using the secure Web Crypto API. Free, instant, in-browser.
HTTP Status Codes
Look up any HTTP status code (200, 301, 404, 500…) with its meaning and category. Free, instant, searchable reference.
MIME Type Lookup
Find the MIME type for any file extension, or the extensions for a MIME type. Free, instant, searchable reference.
CSS Gradient Generator
Create linear and radial CSS gradients visually and copy the code. Free, instant, in-browser gradient generator.
CSS Box Shadow Generator
Design CSS box-shadows visually with sliders and copy the code. Free, instant, in-browser box-shadow generator.
Cron Expression Explainer
Explain a cron expression in plain English and see its next run times. Free, instant, in-browser cron parser.
JSON to YAML Converter
Convert JSON to YAML and YAML back to JSON instantly. Free, private, in-browser converter with validation.
Regex Tester
Test regular expressions against your text with live match highlighting and capture groups. Free, instant, in-browser regex tester.
Barcode Generator
Generate barcodes (CODE128, EAN, UPC and more) from any text and download as PNG. Free, instant, in-browser.
About these developer tools
Every tool here runs entirely in your browser — your files and text never leave your device, there's no sign-up, and there are no usage limits. Pick a tool above to get started, or browse the full A–Z index.