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Free Online Developer Tools

Professional-grade tools for developers — format, validate, test, and debug directly in your browser. 100% client-side, zero data leaves your device.

100% Client-SideSyntax HighlightingKeyboard ShortcutsNo Sign-upDark ModeFree Forever
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Markdown Editor & Viewer

Free online Markdown editor with live preview, syntax-highlighted code blocks, formatting toolbar, rich text copy, and export to HTML & MD. 100% client-side.

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Regex Tester & Builder

Build, test, and debug regular expressions with real-time match highlighting, a token-by-token pattern explainer, 30+ ready-to-use templates, find & replace, and code generation in JavaScript, Python, Go, and PHP.

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Diff Checker

Free online diff checker & code comparison tool. Compare text, code, JSON, XML, and more with syntax highlighting, side-by-side view, and detailed diff statistics. 100% client-side.

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Code Formatter & Minifier

Beautify or minify JSON, JavaScript, CSS, and HTML code online for free. Instant code formatter, beautifier, and minifier with syntax highlighting.

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Base64 Encode & Decode Online

Encode and decode Base64 strings instantly online. Convert text to Base64, decode Base64 to text with full UTF-8 and emoji support. Free and fast.

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JWT Decoder

Free online JWT decoder and parser. Decode JSON Web Tokens instantly, inspect headers, payloads, and claims with color-coded visualization, token timeline, security warnings, and claim-level copy — all 100% client-side.

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Color Palette Generator

Generate beautiful color palettes, check WCAG contrast, simulate color blindness, and extract colors from images — free online color scheme generator.

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JSON Formatter

Free online JSON formatter, validator, and beautifier with tree view, auto-repair, TypeScript generator, and statistics dashboard. 100% client-side.

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Why Use ToolsMint Developer Tools?

100% Free Forever

All tools are completely free with no daily limits, no watermarks, and no premium tiers. Use as much as you want.

Complete Privacy

Everything runs in your browser using client-side JavaScript. Your data never leaves your device — no uploads, no server processing.

No Signup Required

Start using any tool instantly. No accounts, no email verification, no passwords to remember.

Works on Any Device

Responsive design works perfectly on desktop, tablet, and mobile. All you need is a modern web browser.

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