Free Online Developer Tools - 30+ Tools Run Locally in Your Browser
All tools run locally in your browser. Your data never leaves your device. Safe, fast, and free.
Complete list of all developer tools
⭐ Featured Tools
⭐ Top Tools
📚 Learning
JSON Formatter
Beautify, minify and validate JSON data
JSON to CSV
Convert JSON to CSV format
JSON Compare & Diff Tool
Compare two JSON objects and visualize differences with highlighting
Markdown Editor
Real-time preview, GFM support, export PDF
Text Diff
Compare differences between two texts
Regex Tester
Test regular expressions in real-time
Timestamp Converter
Unix timestamp to datetime converter
Base64 Encoder/Decoder
Base64 encoding and decoding for text and images
UUID Generator
Generate UUID v4 in bulk
Password Generator
Generate secure passwords with strength meter
QR Code Generator
Convert text to QR code
URL Encoder/Decoder
URL encoding/decoding and parameter parsing
Color Picker
Color format conversion and contrast detection
Hash Calculator
Calculate SHA hash values for text
JWT Decoder
Parse JSON Web Tokens
Unit Converter
Length, weight, temperature conversion
Cron Expression
Visually generate cron expressions
Text Statistics
Count words, characters, and reading time
Random Data Generator
Generate various types of test data
CSS Shadow Generator
Visually generate box-shadow styles
Gradient Generator
Create linear or radial gradients
Placeholder Image Generator
Generate custom placeholder images
Image Format Converter
Convert image formats (PNG, JPG, WebP)
Image Compressor
Compress image size and optimize quality
SVG Optimizer
Optimize SVG code and reduce file size
Favicon Generator
Generate various sizes of website icons
PDF Generator
Convert Markdown to PDF documents
Math Function Plotter
Plot mathematical function graphs
Chart Generator
Create data visualization charts
Flowchart Diagram
Create diagrams with Mermaid
Why Choose AI-TOL Tools?
Professional tools designed with your privacy in mind
🔒 Privacy-First Architecture
Every tool on AI-TOL runs entirely in your browser using client-side JavaScript. We never upload your data to any server. Whether you're formatting JSON, generating passwords, or processing images, all operations happen locally on your device. This means your sensitive information—API keys, passwords, confidential data—never leaves your computer.
⚡ Professional Quality Standards
Our tools are built with the same standards used in professional development environments. JSON validators catch syntax errors instantly, regex testers highlight matches in real-time, and code formatters enforce consistent styling. We focus on accuracy and reliability, ensuring you get results you can trust in your daily work.
🚀 Zero Friction Experience
No account registration required. No usage limits. No waiting in queues. Just open a tool and start working immediately. Our tools load instantly, process data in milliseconds, and work offline once loaded. Whether you're at your desk or on the go, your tools are always available without barriers.
How Our Tools Work
Simple, secure, and built with modern web technologies
Client-Side Processing
Unlike traditional online tools that send your data to remote servers, all our tools use advanced JavaScript APIs to process data directly in your browser. The Web Crypto API handles encryption operations, the File API manages document uploads, and modern JavaScript engines perform complex calculations—all without a single network request for data processing.
Instant Results, Complete Privacy
Because everything runs locally, you get immediate feedback. No waiting for server responses, no network latency, no file size limitations. Your workflow stays uninterrupted while maintaining complete data privacy. This approach also means our tools work offline after the first page load, perfect for situations with unreliable internet connections.
Open and Auditable Code
Our code is built with modern web standards that anyone can inspect. We use well-documented JavaScript frameworks and follow best practices in security and performance. Every tool's logic is transparent—you can view the source code in your browser's developer tools to verify exactly how your data is being processed.
Common Use Cases
How developers and creators use AI-TOL tools every day
API Development & Testing
Quickly format and validate JSON responses from REST APIs. Test regex patterns against sample data. Decode and inspect JWT tokens to verify authentication claims. Convert timestamps to readable dates for log analysis. Developers use these tools dozens of times daily when building and debugging web services.
Content Creation & Publishing
Writers and editors use our Markdown editor to draft blog posts and documentation. Generate secure passwords for new accounts. Create QR codes for print materials. Convert file formats for different publishing platforms. Compress images to meet website size requirements while maintaining quality.
Security & Privacy Tasks
Generate strong, unique passwords for every account. Hash sensitive data using industry-standard algorithms. Encode and decode Base64 strings for data transmission. Create UUIDs for unique identifiers. Security professionals rely on these tools for quick, secure operations without exposing sensitive data to online services.
Design & Frontend Development
Generate color palettes and gradients for UI designs. Create placeholder images for layout prototyping. Convert between color formats (HEX, RGB, HSL) for CSS. Test CSS shadows and adjust parameters visually. Designers use these tools to speed up their workflow and explore design options quickly.
Data Processing & Conversion
Convert JSON to CSV for spreadsheet analysis. Transform timestamp formats between timezones. Calculate unit conversions for scientific or business data. Generate test data with random values for development. Process text to analyze word frequency and statistics. These tools handle routine data tasks without needing complex software.
About AI-TOL
Built by developers, for developers
Our Story
AI-TOL began as a personal project born from frustration with existing online solutions. As a developer constantly needing quick format conversions, validations, and data transformations, I found myself hesitant to upload sensitive API responses, configuration files, or authentication tokens to random online services. The solution was clear: build applications that run entirely in the browser using client-side JavaScript. What started as a personal toolkit grew into a comprehensive suite of 30+ utilities used daily by developers, content creators, and security professionals worldwide. Each feature exists because someone actually needed it for real work—not to fill a feature matrix or chase trends.
Our Mission
We believe essential utility software should be private, accessible, fast, and free. AI-TOL isn't a startup backed by venture capital—it's a passion project maintained by developers who use these utilities every day. We don't track users, require email addresses, or serve ads that clutter workflows. When using AI-TOL, you're not the product—you're simply completing tasks with software that respects your privacy and time.
Technology & Performance
Built for speed, designed for privacy
Modern Web Technology Stack
AI-TOL is built with modern web technologies that prioritize both performance and security. Our frontend uses Astro for fast static site generation, React for interactive components, and Tailwind CSS for responsive designs. TypeScript ensures type safety and robust code quality. The key advantage lies in your browser: we leverage modern JavaScript engines, the Web Crypto API for cryptographic operations, the Canvas API for image processing, and the File API for document handling—all without sending information to a server.
Why Client-Side Processing Matters
Traditional online applications upload your content to a server, process it, and send back the result. This introduces network latency, requires server infrastructure, and creates security risks. AI-TOL applications process everything locally. The result includes immediate feedback, complete confidentiality (information never leaves your device), and offline functionality (utilities work without internet after initial loading). Modern browsers offer substantial computing power—AI-TOL utilizes this capability to deliver responsive performance on the web.
Frequently Asked Questions
Common questions about AI-TOL
Q1. Are my files processed locally?
A: Yes. All processing happens in your browser using JavaScript. Your files, text, passwords, and sensitive information never leave your device. You can verify this by disconnecting from the internet after loading a page—the utilities will still function effectively.
Q2. Do I need to create an account?
A: No account, email, or registration is required. Simply open any utility and begin using it. We don't track individual users or collect personal information. The only data collected is anonymous analytics (page views, general location, device type) through Google Analytics to help improve our service.
Q3. Are there limits on file size or usage?
A: There are no artificial limits or paywalls. The utilities handle large files (up to 10MB for JSON processing, more for images). Use them as much as needed—there are no quotas, rate limits, or premium tiers. The only practical limits are your browser's memory and processing capabilities.
Q4. How is this service free?
A: AI-TOL operates as a passion project, not a commercial product. Basic hosting costs are covered through minimal advertising (Google AdSense). There's no venture capital pressure to maximize revenue, no subscription fees, and no features locked behind paywalls. Access is free because essential utilities should be available to everyone.
Q5. Can I use AI-TOL for commercial projects?
A: Yes. All utilities are available for personal, educational, or commercial purposes. Whether you're a freelance developer, working at a startup, or part of a large enterprise, you're welcome to incorporate these solutions into your workflow. No licensing fees, no usage restrictions—just functional, privacy-focused software.
Q6. What browsers and devices are supported?
A: AI-TOL functions on any modern browser with JavaScript support: Chrome, Firefox, Safari, Edge, and their mobile counterparts. The utilities are fully responsive and work on desktop computers, tablets, and smartphones. We recommend using the latest version of your preferred browser for optimal performance and security.
Why Choose Us
Data Security
All processing done locally, data never leaves browser
Fast Response
No network requests, instant data processing
Dark Mode
Switch between light and dark themes to protect your eyes