Developer Tools
Essential utilities for developers: format, validate, convert, and debug your code and data. All tools run in your browser—no server uploads, completely free, no signup required.
JSON Formatter
Format, validate, and beautify JSON with syntax highlighting
PopularBase64 Encoder/Decoder
Encode and decode Base64 strings, images, and files
JWT Decoder
Decode and inspect JWT tokens without verification
URL Encoder/Decoder
Encode and decode URLs and query parameters
CSV to JSON
Convert CSV data to JSON format instantly
YAML to JSON
Convert YAML to JSON with proper formatting
HTML Minifier
Minify HTML code to reduce file size
Regex Tester
Test and debug regular expressions with live matching
PopularXML to JSON
Convert XML data to JSON format with validation
SQL Formatter
Format and beautify SQL queries with indentation
UUID Generator
Generate v4 UUIDs with bulk generation support
Markdown to HTML
Convert Markdown to HTML with live preview
HTML Entity Encoder
Encode and decode HTML entities for safe display
Cron Expression Generator
Create cron expressions with visual builder
SHA-256 Hash Generator
Generate SHA-256, SHA-1, and MD5 hashes
GraphQL Formatter
Format and beautify GraphQL queries
Base64 to PDF
Convert Base64 strings to PDF files with preview
URL Parser
Parse URLs and extract query parameters
Beautify HTML
Format and prettify HTML code with indentation
Minify CSS
Compress and optimize CSS code for production
Why Use Online Developer Tools?
Online developer tools provide instant access to essential utilities without installing software or running command-line scripts. Whether you're debugging API responses, validating data formats, or converting between file types, these browser-based tools offer convenience, speed, and security.
Popular Use Cases
🔍 API Development & Testing
Format and validate JSON responses, decode JWT tokens, test regex patterns for input validation, and encode/decode URL parameters for API calls.
📊 Data Transformation
Convert between CSV, JSON, and YAML formats for data migration, configuration management, and integration with different systems and APIs.
🔐 Security & Encoding
Encode sensitive data with Base64, decode JWT tokens to inspect claims, and properly encode URLs to prevent injection attacks and ensure data integrity.
⚡ Performance Optimization
Minify HTML, CSS, and JavaScript to reduce file sizes, optimize load times, and improve website performance for better user experience and SEO.
Frequently Asked Questions
Are these developer tools free?
Yes, all developer tools on PromptTools are completely free with no signup, no credit card, and no hidden fees. Use them as much as you need for personal or commercial projects.
Is my data secure?
Absolutely. All tools run entirely in your browser using client-side JavaScript. Your data never leaves your computer and is not uploaded to any server, ensuring complete privacy and security.
Do I need to install anything?
No installation required. These are web-based tools that work directly in your browser. Just visit the page, paste your data, and get instant results. Works on any device with a modern web browser.
Can I use these tools for large files?
Most tools can handle files up to several megabytes. For very large files, performance depends on your browser and device capabilities. We recommend testing with a sample first for files over 5MB.