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Free Developer Tools - Code, Debug & Ship Faster

Spending too much time on boilerplate and debugging? Our free developer tools help you format data, test endpoints, explain code, generate SQL, and create documentation — all in your browser with zero setup. Ship cleaner code faster without switching between desktop apps.

15 Free ToolsNo Signup Required

API Tester

Send REST API requests with custom headers, body, and params. View structured responses.

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Code Explainer

Get line-by-line breakdowns of code logic, syntax, and purpose in plain language.

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Code Refactorer

Refactor code for readability, performance, and maintainability with side-by-side diffs.

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CSS Gradient Generator

Design linear, radial, and conic gradients with a visual editor and copy the CSS.

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HTML Previewer

Write HTML/CSS/JS and see the rendered output alongside the editor in real time.

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JSON Formatter & Validator

Validate syntax, beautify structure, and navigate JSON in a collapsible tree view.

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Newsletter Curator

Compile and organize newsletter content with topic suggestions and draft text.

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Product Description Generator

Write e-commerce product listings with features, specs, and benefit-focused copy.

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README Generator

Build structured README.md files with project overview, installation, and usage examples.

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Regex Tester

Test regular expressions with real-time match highlighting and a quick-reference cheat sheet.

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Resume Builder

Build ATS-friendly resumes with structured sections and multiple professional templates.

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SQL Generator

Describe queries in plain English and get formatted SQL with proper joins and clauses.

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Uptime Monitor

Track website availability with downtime alerts, status pages, and incident history.

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URL Shortener

Create short links with custom aliases, click analytics, and QR code generation.

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Web Analyzer

Run technical audits on any URL covering SEO, performance, and accessibility with scored reports.

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About Our Developer Tools - Code, Debug & Ship Faster

ToolmetryAI's developer tools are built for programmers who want to move fast without cluttering their workflow. Format and validate JSON with error highlighting, test REST APIs with custom headers and payloads, or debug regular expressions with real-time match previews. Need SQL? Describe what you want in plain English and get a syntactically correct query. Refactoring legacy code? Paste it in and receive a cleaner, more maintainable version with side-by-side diffs. You will also find a visual CSS gradient builder, a live HTML/CSS/JS previewer, a README generator that structures your GitHub repos, and a URL shortener with click analytics. Every tool is browser-based, free, and requires no installation — so you can open a tab, get your answer, and get back to building.

Frequently Asked Questions

Are these developer tools free to use?
Yes. All developer tools are completely free with no signup, no watermarks, and no usage caps. Open any tool and start using it immediately.
Is my code or data sent to a server?
Most tools process everything locally in your browser. Tools that use AI (Code Explainer, Code Refactorer, SQL Generator) send your input to our AI backend for processing — your data is never stored or shared.
Which programming languages does the Code Explainer support?
The Code Explainer works with all major languages including JavaScript, Python, Java, C++, Go, Rust, PHP, and more. Paste any snippet and receive a line-by-line breakdown.
Can I use the API Tester instead of Postman?
The API Tester covers the most common REST testing scenarios — custom headers, body payloads, and auth tokens. For advanced features like collections and automated testing, a desktop client may offer more.