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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
HTTP

HTTP Status Code Lookup

Look up HTTP status codes with plain-English meanings, API guidance, SEO notes, retry rules, cache tips, headers, and copy-ready response examples.

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🆔

UUID Generator

Generate UUID v4, UUID v7, and GUID lists locally with bulk output, format variants, timestamp insight, copy, and TXT/CSV/JSON download.

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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

Compare text, code, JSON, XML, and config files side by side with syntax highlighting, inline view, whitespace controls, and private browser-based diffing.

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✨

Code Formatter & Minifier

Format, beautify, or minify JSON, JavaScript, CSS, and HTML instantly with Monaco-powered editing, validation, upload/download, and private browser processing.

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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

Decode JWT tokens online, inspect header and payload claims, read exp and iat timestamps, and spot auth mistakes without sending tokens anywhere.

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🎨

Color Palette Generator

Generate color palettes from scratch or from images, build Tailwind-ready scales, check WCAG contrast, and simulate color blindness in your browser.

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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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🧾

XML Formatter

Free online XML formatter, validator, minifier, and tree viewer with XPath copy, attribute sorting, XML stats, upload, and download. 100% client-side.

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🌿

Branch Name Generator

Generate clean, convention-compliant git branch names from task descriptions, JIRA tickets, or any text input. Supports 12 prefix types, 4 naming conventions, and auto-detects ticket IDs.

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📊

CSV JSON Converter

Convert CSV to JSON and JSON to CSV with quoted-field parsing, nested object flattening, delimiter controls, copy, and download.

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🔗

URL Encoder Decoder

Encode URI components, encode full URLs, decode escaped URL strings, parse query parameters, and batch-process lines locally.

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🕒

Unix Timestamp Converter

Convert Unix epoch seconds or milliseconds to readable dates, convert dates back to timestamps, and batch-convert values.

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👁️

Color Contrast Checker

Check foreground and background color contrast for WCAG AA and AAA, with live preview, CSS output, and readable results.

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⏱️

Cron Expression Generator

Build, validate, explain, and copy cron expressions with next-run previews, plain-English schedule summaries, deployment snippets, and risk warnings.

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XML

XML Sitemap Generator

Generate a clean sitemap.xml from pasted URLs with dedupe, lastmod, robots.txt snippet, SEO limit checks, and XML, TXT, or CSV export.

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MD

HTML to Markdown Converter

Convert HTML to clean Markdown locally with table and code support, upload, copy, download, and practical cleanup diagnostics.

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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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