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Free Developer Tools

Fast, private, browser-based utilities for developers — format and validate JSON, encode Base64, check password strength, preview meta tags, and test color contrast. No signup, nothing sent to a server.

JSON Formatter & Validator

Format, validate, and minify JSON instantly. Detect syntax errors with line numbers. Copy or download the result.

  • Developer
  • JSON
  • Validator

Base64 Encoder / Decoder

Encode plain text to Base64 or decode Base64 back to text instantly. Supports files and Unicode.

  • Developer
  • Encoding
  • Utility

Color Contrast Checker (WCAG)

Check if your foreground/background color combination passes WCAG AA and AAA accessibility standards.

  • Design
  • Accessibility
  • WCAG

Password Strength Checker

Analyze password entropy, estimate crack time, and get specific improvement tips. 100% local — never sent to a server.

  • Security
  • Privacy
  • Utility

Meta Tags Preview Tool

Preview how your page looks in Google, Twitter/X, and LinkedIn before publishing. Generates ready-to-copy HTML tags.

  • SEO
  • Developer
  • Social Media

Related Guides

How to Format and Validate JSONRead →What Is Base64 Encoding?Read →How to Create a Strong PasswordRead →Meta Tags for SEORead →WCAG Color Contrast GuideRead →JSON vs XML vs YAMLRead →

Frequently Asked Questions

Are these developer tools free?

Yes — every tool is free, with no signup and no ads. They run entirely in your browser.

Is my data safe?

Yes. These tools process everything client-side, so your code, text, and credentials never leave your device.

Do they work offline?

Once the page has loaded, the tools keep working without a network connection.

Can I use them on mobile?

Yes, all tools are responsive and work on phones, tablets, and desktops.

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