Free Online Tools
Developer Tools
Utilities every developer needs — format, encode, decode, hash, and generate — all in one place.
All Developer Tools
JSON Formatter
PopularFormat, validate and beautify JSON
.gitignore Generator
NewGenerate .gitignore files for any tech stack
JSON to CSV
Convert JSON data to CSV format
CSV to JSON
Convert CSV to JSON format
Base64 Encoder/Decoder
Encode or decode Base64 strings
URL Encoder/Decoder
Encode or decode URL strings
HTML Entity Encoder
Encode/decode HTML entities
Hash Generator
Generate MD5, SHA1, SHA256, SHA512 hashes
UUID Generator
Generate random UUIDs (v4)
Password Generator
Generate strong random passwords
Regex Tester
Test and debug regular expressions
JWT Decoder
Decode and inspect JWT tokens
HTML Formatter
Format and beautify HTML code
CSS Formatter
Format and beautify CSS code
Number Converter
Convert between binary, decimal, hex, octal
Cron Parser
Parse and explain cron expressions
SQL Formatter
Format and minify SQL queries with dialect support
XML Formatter
Format, minify and validate XML documents
YAML ↔ JSON Converter
Convert between YAML and JSON formats
Color Contrast Checker
Check WCAG 2.1 color contrast ratios for accessibility
About Developer Tools
SimplyToolbox's developer tool collection covers everyday needs for web developers, backend engineers, and DevOps professionals. Format and validate JSON, encode and decode Base64 strings, generate MD5/SHA hashes, test regular expressions with live match highlighting, decode JWT tokens, generate UUIDs, format SQL queries, convert YAML to JSON, parse cron expressions, and generate secure passwords. Everything runs in your browser with no data sent to any server — safe for use with sensitive tokens, passwords, and proprietary code.
100% Private
All processing happens in your browser. Your files are never uploaded to our servers.
Instant Processing
No waiting for server responses. Tools run immediately using WebAssembly technology.
Always Free
No subscriptions, no watermarks, no file size limits. Every tool is free forever.