Free Developer Tools — Thirty-Eight Browser Utilities for Dev and QA Work

Thirty-seven tools for the full developer workflow

Built for developers, QA engineers, and anyone working regularly with APIs, tokens, or data formats.

Each tool does one job immediately: JSON Formatter formats or minifies JSON and reports errors by line. JSON Diff Checker deep-diffs two JSON objects recursively — added keys in green, removed in red, changed values in yellow. JSON to YAML Converter converts any valid JSON to clean, indented YAML — validates first, handles nested objects, arrays, and all scalar types. YAML to JSON Converter converts YAML — Kubernetes manifests, Ansible playbooks, config files — to clean, formatted JSON. Server-side. XML Formatter & Validator formats or minifies XML using the browser’s native DOMParser — reports parse errors with exact line and column. CSS Formatter + Validator beautifies or minifies CSS and reports syntax errors with exact line and column. 100% in-browser. JWT Decoder reads token claims without the signing key. Text Diff compares two text blocks line by line. Hash Generator produces MD5, SHA-1, SHA-256, and SHA-512 hashes from text or files — all four in one pass. Base64 encodes and decodes in both standard and URL-safe modes. Binary Translator converts across decimal, binary, hex, and octal. Case Converter outputs 12 formats simultaneously. Regex Tester highlights matches and capture groups inline. UUID Generator produces v1, v4, or v5 UUIDs in single or bulk mode. Unix Timestamp Converter shows UTC and local time for any epoch value. Timezone Converter converts any time between two of 175 IANA timezones with DST awareness. URL Encoder / Decoder handles percent-encoding and detects double-encoding. URL Shortener compresses long URLs to a permanent at-use.com short link with QR code output. Cron Expression Builder builds or decodes cron strings and previews the next five fire times. Number Base Converter converts between binary, decimal, hex, and octal with two’s complement and nibble-grouping support. Markdown to HTML converts CommonMark + GFM Markdown to HTML with live preview and a download option. HTML Entity Encoder / Decoder encodes special characters (< > & " ') to HTML entities and decodes entities back to plain text, all in the browser. Code to Image Converter turns any code snippet into a shareable PNG or JPEG — eight themes, 40+ languages, 2× resolution. Runs entirely in the browser. Color Picker shows the HEX, RGB, and HSL values for any color you pick or type, with one-click copy for each format. Hex to RGB Color Converter converts between HEX, RGB, and HSL — all three outputs update live as you type. Password Generator produces cryptographically secure passwords using the browser’s Web Crypto API — nothing sent to a server. QR Code Generator creates QR codes from URLs, text, WiFi credentials, or contact cards — download as PNG or SVG. QR Code Reader decodes QR codes from an uploaded image or live camera scan, entirely in the browser. Word Counter counts words, characters, sentences, and paragraphs instantly with reading time and keyword frequency.