🛠️ Developer Tools
A toolbox for everyday development tasks. Format, encode, decode and generate without leaving the browser or pasting sensitive data into sketchy sites.
JSON Formatter
Beautify, minify and validate JSON instantly in your browser.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text instantly.
UUID Generator
Generate random RFC-4122 version-4 UUIDs in bulk.
URL Encoder / Decoder
Percent-encode text for URLs or decode it back to plain text.
JWT Decoder
Decode a JWT to inspect its header and payload claims.
Hash Generator
Generate SHA-256, SHA-1, SHA-384 and SHA-512 hashes of text.
Unix Timestamp Converter
Convert epoch timestamps to dates and dates back to epoch.
Number Base Converter
Convert between binary, octal, decimal and hexadecimal.
Regex Tester
Test regular expressions against sample text with live matches.
Password Generator
Generate cryptographically random passwords with one click.
HTML Entity Encoder / Decoder
Escape HTML special characters or decode entities back to text.
JSON to CSV Converter
Turn a JSON array of objects into clean, spreadsheet-ready CSV.
CSV to JSON Converter
Convert CSV (with a header row) into a clean JSON array of objects.
XML Formatter
Beautify or minify XML with proper indentation, validated in-browser.
SQL Formatter
Format messy SQL into readable, indented queries instantly.
Markdown to HTML Converter
Convert Markdown to clean HTML with a live preview.
Cron Expression Generator
Build and understand cron schedules with presets and a plain-English description.
AI Token Counter
Estimate how many tokens your prompt uses and what it costs.
JSON to TypeScript
Generate TypeScript interfaces from a JSON sample instantly.
CSS Minifier
Minify CSS by stripping comments and whitespace to shrink file size.
JSON Escape / Unescape
Escape text into a JSON string value, or unescape it back.
Query String Parser
Decode a URL's query string into a readable key/value table and JSON.
Random Number Generator
Generate random numbers in a range, with no-duplicates and sort options.
Password Strength Checker
Estimate password entropy and crack time — privately, in your browser.
Dice Roller
Roll dice with standard notation like 2d6+3 — for RPGs and games.
Caesar Cipher
Encrypt and decrypt text with a Caesar shift — or brute-force all 26.
ROT13 Encoder / Decoder
Apply ROT13 to hide or reveal text — the same button does both.
Unicode Converter
Convert text to Unicode code points (U+XXXX) and escapes, and back.
Base64 to Image
Decode Base64 to an image preview, or encode an image to a data URI.
Markdown Table Generator
Fill a grid and get a clean GitHub-flavored Markdown table.
JSON Repair
Fix common JSON errors: single quotes, trailing commas, unquoted keys.
Aspect Ratio Calculator
Resize dimensions to a ratio, or find the ratio of any width and height.
PX to REM Converter
Convert between px, rem and em for CSS using your root font size.
Guides & explainers
How to Fix Invalid JSON
A practical guide to JSON parse errors: how to read the error message, the eight most common causes (trailing commas, single quotes, unquoted keys) and how to fix each.
GuideWhat is Base64 Encoding?
Base64 explained: what it does, why binary data needs it, how the 3-bytes-to-4-characters scheme works, the = padding, URL-safe Base64 — and why it is not encryption.
GuideWhat is a JWT (JSON Web Token)?
JWTs explained: the header.payload.signature structure, what claims are, why signed is not encrypted, how verification works and where JWTs are used.
GuideURL Encoding (Percent-Encoding), Explained
Why URLs need percent-encoding, what %20 means, reserved vs unreserved characters, encodeURI vs encodeURIComponent, and the bugs (double-encoding) to avoid.