Developer calculators
JSON, Base64, hashes, JWT, timestamps. 15 tools
Most popular
Base64 Encode & Decode
Encode text to Base64 or decode Base64 back to text, with full UTF-8 and URL-safe Base64 support.
Hash Generator (MD5, SHA-1, SHA-256, SHA-512)
Compute MD5, SHA-1, SHA-256 and SHA-512 hashes of any text instantly, right in your browser.
JSON Formatter & Validator
Pretty-print, minify and validate JSON, with the exact line and column of any syntax error.
JWT Decoder
Decode a JSON Web Token to read its header and payload claims, with issue and expiry times in plain dates.
Password Generator
Create strong random passwords with your choice of length and character types, and see their entropy in bits.
Unix Timestamp Converter
Convert Unix epoch timestamps in seconds or milliseconds to ISO 8601, UTC and local time — or turn a date back into a timestamp.
UUID Generator
Generate random version 4 UUIDs (GUIDs) in bulk, using your browser's cryptographically secure random generator.
More developer tools
Color Converter (HEX, RGB, HSL, HSV, CMYK)
Convert any color between HEX, RGB, HSL, HSV and CMYK — paste it in any format and get all the others.
Cron Expression Explainer
Translate a 5-field cron expression into plain English and list its next scheduled run times.
CSV to JSON Converter
Convert CSV or TSV data into a JSON array, with quoted fields, auto-detected delimiters and optional number detection.
HTML Entity Encoder & Decoder
Escape text for safe use in HTML (< & "…) or turn HTML entities back into plain characters.
JSON to CSV Converter
Convert a JSON array of objects into CSV for Excel or Google Sheets, flattening nested fields into columns.
Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal (or any base from 2 to 36), with no size limit.
Regex Tester
Test a JavaScript regular expression against sample text and see every match, its position and its capture groups.
URL Encode & Decode
Percent-encode text for use in URLs and query strings, or decode %20-style escapes back to readable text.