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Free Online Developer Tools, Built for Speed, Privacy, and Simplicity

No login. No installation. No data sent to servers. Just paste, click, and get results instantly.

Whether you're debugging an API response at 2 AM or preparing data for a deployment, you need tools that work the moment you open them. StackDevTools is a free collection of browser-based utilities built for developers, content creators, and anyone who works with data every day.

Every tool runs directly in your browser. Your data stays on your device. Nothing is stored, nothing is logged.

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Our Tools

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JSON Formatter

Format and beautify your JSON data with proper indentation and syntax highlighting. Perfect for making messy JSON readable.

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Age Difference Calculator

Find the exact age gap between two people or dates in years, months, and days. Quick, accurate, and easy to use for relationships, family, or research.

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Discount Calculator

Quickly calculate discounts on products or services. Find out the final price after applying percentage or flat discounts easily and accurately.

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Text Repeater

Instantly repeat any text multiple times with custom separators. Perfect for testing, social posts, and quick content generation.

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Slug Generator

Create clean, SEO-friendly slugs for blogs, products, and pages in one click. Perfect for readable and optimized URLs.

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Case Converter

Easily change the text capitalization online. Convert to uppercase, lowercase, title case, sentence case, and more instantly.

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JSON to XML Converter

Easily convert JSON data into XML format online. Fast, accurate, and code-free tool to transform JSON to XML instantly.

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JSON to YAML Converter

Easily convert JSON data into YAML format online. Fast, accurate, and code-free tool to transform JSON to YAML instantly.

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Text Difference Checker

Compare two large text blocks side by side and highlight differences with color-coded changes. Useful for code, documents, or long text revisions.

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Why Developers Choose StackDevTools

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Instant Results

Every tool produces output the moment you paste or type. No waiting, no loading screens.

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Privacy First

All processing happens in your browser. We don't store your data, log your inputs, or share anything with third parties.

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Always Free

No subscriptions. No freemium paywalls. Every tool is 100% free with no feature limits.

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Pick a tool above and get results in under 10 seconds — no account, no credit card, no setup.

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