30+ Free Online Developer Tools You Should Bookmark in 2026

Why Browser-Based Dev Tools?

Sometimes you just need to quickly format some JSON, test a regex, or decode a JWT. Installing a desktop app or VS Code extension for every small task is overkill. Browser-based tools load instantly, work on any device, and require no setup.

Here are 30+ tools every developer should have bookmarked.

Code Formatting and Linting

JSON

• JSON Formatter - Pretty-print and validate JSON with syntax highlighting
• JSON Validator - Check if your JSON is valid and find errors
• JSON Path Finder - Click any value to get its JSON path
• JSON to TypeScript - Generate TypeScript interfaces from JSON

CSS

• CSS Formatter - Beautify minified CSS
• CSS Minifier - Compress CSS for production
• CSS Grid Generator - Visual grid layout builder

JavaScript and SQL

• JavaScript Beautifier - Format and clean up JS code
• SQL Formatter - Format SQL queries with proper indentation

Encoding and Conversion

• Base64 Encoder/Decoder - Encode and decode Base64 strings
• URL Encoder - Percent-encode URLs and query strings
• HTML Entity Encoder - Convert special characters to HTML entities
• JSON to YAML - Convert between JSON and YAML formats
• JSON to CSV - Turn JSON arrays into CSV files
• XML to JSON - Parse XML into JSON objects

Testing and Debugging

• Regex Tester - Test regular expressions with live highlighting
• JWT Decoder - Decode and inspect JWT tokens
• API Tester - Send HTTP requests and inspect responses
• HTTP Status Codes - Quick reference for all HTTP status codes
• Cron Expression Builder - Build and test cron schedules visually

Generators

• UUID Generator - Generate v4 UUIDs in bulk
• Hash Generator - MD5, SHA-1, SHA-256, SHA-512 hashing
• Password Generator - Cryptographically secure passwords
• Lorem Ipsum Generator - Placeholder text for mockups
• API Key Generator - Random API keys in various formats

CSS Visual Builders

These tools let you design CSS visually and copy the generated code:

• Box Shadow Generator - Design shadows with live preview
• CSS Gradient Generator - Linear and radial gradients
• Border Radius Generator - Custom corner radius values
• Glassmorphism Generator - Frosted glass effects
• Flexbox Playground - Interactive flexbox layout tester
• CSS Filter Generator - blur, brightness, contrast and more
• CSS Animation Generator - Keyframe animations

Network and Server

• DNS Lookup - Query DNS records for any domain
• Subnet Calculator - Calculate subnets, hosts, and CIDR ranges
• What's My IP - Check your public IP address
• Nginx Config Generator - Generate Nginx server blocks

Why We Built These

All tools on ToolSpark run entirely in your browser. Your data never leaves your device. There is no tracking, no accounts, and no rate limits. Just open the tool and use it.

Bookmark the ones you use most. Your future self will thank you.