Tool Categories
Browse our tool collection by category to quickly find what you need
Popular Guides
Learn how to use our tools to solve real problems
Developer's Guide to Optimizing Website Loading Speed (Complete 2025 Guide)
Complete guide for developers on optimizing website loading speed in 2025. Learn about Core Web Vitals, image compression, minification, and how to use FastOS Tools for performance optimization.
How to Batch Rename Files: Complete Guide with Free Tools (2025)
Learn how to batch rename files efficiently in 2025. Compare OS native methods, online tools, and discover FastOS Tools solutions for file renaming workflows.
How to Compress PDF Files: Complete Beginner's Guide (2025)
Learn how to compress PDF files effectively in 2025. Compare online vs offline tools, step-by-step instructions, common mistakes, and optimization tips. Reduce PDF size without quality loss.
How to Reduce Image Size Without Quality Loss: Complete Guide for Photographers & Designers (2025)
Learn how to reduce image file size without losing quality in 2025. Understand compression principles, compare formats (PNG/JPG/WebP), and discover optimization techniques for photographers and designers.
Top 10 Best Lightweight Online Tools Comparison (2025)
Compare the 10 best lightweight online tools in 2025. Detailed analysis of features, pros, cons, and use cases. Includes FastOS Tools as a comprehensive solution.
User Use Cases
See how different users use our tools to solve real problems
Converting Legacy CSV Data to JSON for Modern API Integration
A developer workflow for converting CSV exports from legacy systems into JSON format for API consumption, handling edge cases like nested data, special characters, and data type conversion.
Debugging API Authentication Failures with JWT Decoder
A developer workflow for troubleshooting 401/403 errors in production APIs by decoding JWT tokens, comparing working vs. broken requests, and identifying authentication issues quickly.
Managing Event Check-ins and Networking with QR Code Tools
Learn how event organizers use QR code generators and decoders to streamline check-ins, share WiFi credentials, and facilitate networking at conferences and workshops.
Generating and Managing Secure Passwords for Team Accounts
A practical guide for IT administrators and team leads on using password generators to create strong, unique passwords for shared accounts, service integrations, and team resources.
Optimizing Website Performance by Converting Images to WebP Format
A web developer workflow for converting website images to WebP format to improve page load times, reduce bandwidth costs, and enhance user experience while maintaining image quality.
Organizing Company Assets as a New Hire Using an Online QR Code Decoder
How a new employee uses an online QR code decoder to extract URLs from labels, PDFs, and packaging, and then organize digital assets into a searchable internal library.
All Tools
Browse our 62 free online tools
JSON Formatter
Format and beautify JSON data online. Validate, minify, and prettify JSON with syntax highlighting.
JSON Validator
Validate JSON syntax and check for errors. Get detailed error messages and line numbers.
Base64 Encoder & Decoder
Encode and decode Base64 strings online. Convert text to Base64 and vice versa instantly.
URL Encoder & Decoder
Encode and decode URL strings online. Convert special characters to URL-safe format and vice versa.
JWT Decoder
Decode and verify JWT tokens online. View JWT header, payload, and signature information.
HTML Encoder & Decoder
Encode and decode HTML entities online. Convert special characters to HTML entities and vice versa.
HTML Minifier
Minify and compress HTML code online. Remove whitespace, comments, and unnecessary characters.
XML Formatter & Validator
Format, validate, and beautify XML documents online. Check XML syntax and indent properly.
YAML ↔ JSON Converter
Convert YAML to JSON and JSON to YAML online. Bidirectional conversion with validation.
CSV ↔ JSON Converter
Convert CSV to JSON and JSON to CSV online. Handle headers, quotes, and delimiters properly.
Text Deduplicator
Remove duplicate lines from text online. Keep unique lines and remove duplicates efficiently.
Text Statistics
Analyze text statistics online. Count words, characters, lines, paragraphs, and more.
Text Case Converter
Convert text case online. Transform to uppercase, lowercase, title case, sentence case, and more.
Regex Tester
Test regular expressions online. Match patterns, test regex, and see results in real-time.
Markdown ↔ HTML Converter
Convert Markdown to HTML and HTML to Markdown online. Bidirectional conversion with formatting.
Text Diff Tool
Compare two texts and find differences online. Highlight additions, deletions, and changes.
UUID Generator
Generate UUIDs (Universally Unique Identifiers) online. Create v1, v4, and custom UUIDs.
Password Generator
Generate secure random passwords online. Customize length, characters, and complexity.
Emoji Converter
Convert emojis to Unicode, UTF-8, and other formats online. Encode and decode emoji characters.
AES Encrypt & Decrypt
Encrypt and decrypt text using AES encryption online. Secure AES-256 encryption with password.
CURL Command Generator
Generate CURL commands from HTTP requests. Convert browser requests to CURL commands easily.
User-Agent Parser
Parse and analyze User-Agent strings. Extract browser, OS, device information from UA strings.
IP Lookup
Look up IP address information. Get location, ISP, and network details for any IP address.
Cron Expression Generator
Generate cron expressions easily. Create cron schedules with a visual interface.
Webhook Tester
Test webhooks online. Simulate webhook requests and inspect payloads in real-time.
Binary ↔ Hex Converter
Convert between binary and hexadecimal numbers online. Fast and accurate conversion tool.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Support multiple timezones.
Base Converter
Convert numbers between different bases (binary, octal, decimal, hexadecimal). Fast and accurate.
URL Parser
Parse and analyze URLs. Extract protocol, domain, path, query parameters, and fragments.
Image Compressor
Compress images online in your browser. Reduce image file size while maintaining quality.
Image to Base64
Convert images to Base64 strings online. Encode images to Base64 format instantly.
Base64 to Image
Convert Base64 strings to images in your browser. Preview and download decoded images.
Image to WebP Converter
Convert images to WebP format online. Optimize images with modern WebP compression.
EXIF Viewer
View EXIF metadata from images online. Extract camera settings, GPS data, and more.
Image Cropper
Crop images online using Canvas. Select and crop image regions with precision.
SVG Compressor
Compress SVG files online. Optimize SVG code and reduce file size.
SVG ↔ PNG Converter
Convert SVG to PNG and PNG to SVG online. Bidirectional conversion with quality control.
PNG ↔ JPG Converter
Convert PNG images to JPG and JPG images to PNG directly in your browser.
PDF Compressor
Compress PDF files online in your browser. Reduce PDF file size without quality loss.
PDF Merger
Merge multiple PDF files into one online. Combine PDF documents easily.
MP3 Converter & Compressor
Convert and compress MP3 audio files online. Optimize audio file size and quality.
Meta Tag Generator
Generate HTML meta tags for SEO. Create meta tags for title, description, Open Graph, and more.
Robots.txt Generator
Generate robots.txt file for your website. Configure search engine crawler access rules.
Sitemap Generator
Generate XML sitemap for your website. Create sitemap files for search engines.
OpenGraph Previewer
Preview how your website appears when shared on social media. Test Open Graph meta tags.
HTTP Headers Viewer
View HTTP response headers of any website. Analyze security headers and server information.
HTTP Status Code Explainer
Explain HTTP status codes. Understand what each status code means and when to use it.
DNS Lookup
Look up DNS records for any domain. Query A, AAAA, MX, TXT, CNAME, and other DNS records.
Web Vitals Checker
Measure Core Web Vitals of your website. Check LCP, FID, CLS, and other performance metrics.
Color Contrast Checker
Check color contrast ratio for WCAG compliance. Ensure your colors meet accessibility standards.
Favicon Generator
Generate favicon from emoji or text. Create PNG favicon files for your website.
Image to Icon Converter
Convert images to icon files (ICO, PNG) in multiple sizes. Create favicons and app icons from any image.
Image Filter
Apply filters and effects to images online. Adjust brightness, contrast, saturation, and apply preset filters like vintage, black & white, and more.
QR Code Decoder
Scan or upload QR codes to extract URLs, text, and other information in your browser.
QR Code Generator
Generate QR codes from URLs, text, or IDs for fast input, sharing, and tracking.
Sliding Puzzle Game
Play the classic 3x3 sliding puzzle game online. Use numbers 1-9 or upload your own image to create a custom puzzle.
Tic Tac Toe Game
Play the classic 3×3 tic tac toe game. Take turns placing X and O, first to get 3 in a row wins.
Emoji Memory Match
Flip cards to find matching emoji pairs. Test your memory and finish in as few moves as possible.
2048 Game
Play the classic 2048 puzzle game. Merge tiles to reach 2048 and beyond.
Rock Paper Scissors
Play rock paper scissors against the computer. Quick, simple, and fun.
Dice Roller
Roll multiple dice with animation. Choose up to 99 dice and instantly see the total.
Keyboard & Mouse Tester
Test your keyboard and mouse online. Visualize key presses and mouse clicks for PC and Mac layouts.
Latest Articles
Get the latest tool usage tips and best practices
Developer's Guide to Optimizing Website Loading Speed (Complete 2025 Guide)
Complete guide for developers on optimizing website loading speed in 2025. Learn about Core Web Vitals, image compression, minification, and how to use FastOS Tools for performance optimization.
How to Batch Rename Files: Complete Guide with Free Tools (2025)
Learn how to batch rename files efficiently in 2025. Compare OS native methods, online tools, and discover FastOS Tools solutions for file renaming workflows.
How to Compress PDF Files: Complete Beginner's Guide (2025)
Learn how to compress PDF files effectively in 2025. Compare online vs offline tools, step-by-step instructions, common mistakes, and optimization tips. Reduce PDF size without quality loss.
How to Reduce Image Size Without Quality Loss: Complete Guide for Photographers & Designers (2025)
Learn how to reduce image file size without losing quality in 2025. Understand compression principles, compare formats (PNG/JPG/WebP), and discover optimization techniques for photographers and designers.
Top 10 Best Lightweight Online Tools Comparison (2025)
Compare the 10 best lightweight online tools in 2025. Detailed analysis of features, pros, cons, and use cases. Includes FastOS Tools as a comprehensive solution.
HTTP Headers Deep Dive: Practical Tips for Debugging and Optimization
An in-depth, example-driven introduction to HTTP headers for developers, covering caching, security, debugging and how to use online tools to inspect and compare real-world requests.