Developer / Tech Tools

Free browser-based developer utilities. All processing runs locally — no uploads, no accounts required.

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JSON Formatter / Validator

Format, minify and validate JSON instantly

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HTML Encoder / Decoder

Encode special characters to HTML entities

Regex Tester

Test regular expressions with live match highlighting

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IP Address Lookup

Get your current public IP address instantly

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CSS Minifier

Minify CSS code for faster page loading

JS Minifier

Minify JavaScript code for production use

Hash Generator

MD5-equivalent SHA-1, SHA-256, SHA-512 hashing

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Unix Timestamp

Convert Unix timestamps to readable dates and back

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JWT Decoder

Decode and inspect JSON Web Token payloads

Markdown Preview

Write Markdown and see formatted HTML preview live

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Dummy Data Generator

Generate JSON, CSV and SQL dummy data rows

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Cool Tips

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Developer / Tech Tools — Guides

Toolzilla's Developer Tools help programmers format JSON, test regex patterns, encode HTML, generate hashes, decode JWTs, minify CSS and JavaScript, preview Markdown, and more — all running locally. Nothing is sent to external APIs, making these tools safe for proprietary code and internal data.

JSON Formatter / Validator — How to Use

Pretty-print, minify, and validate JSON with clear error messages.

Paste your JSON into the input area.
Click Format to beautify or Minify to compress.
Fix any syntax errors highlighted by the validator.

Tip: Validate API responses before integrating into your application.

HTML Encoder / Decoder — How to Use

Convert special characters to HTML entities and back.

Paste text or HTML snippet.
Choose encode or decode.
Copy the safe output for use in templates.

Tip: Encode user input before rendering to prevent XSS vulnerabilities.

Regex Tester — How to Use

Test regular expressions with live match highlighting.

Enter your regex pattern and test string.
Review matched groups and positions.
Refine the pattern until it captures correctly.

Tip: Test edge cases like empty strings and special characters.

Hash Generator — How to Use

Generate SHA-1, SHA-256, and SHA-512 hashes from any text.

Enter the text to hash.
Select the hash algorithm.
Copy the hexadecimal digest.

Tip: Use SHA-256 for file integrity checks and password-free verification workflows.

JWT Decoder — How to Use

Decode JSON Web Token headers and payloads without verifying signatures.

Paste the JWT string.
View decoded header and payload JSON.
Inspect claims like exp, sub, and roles.

Tip: Never paste production secrets into any online tool — decode structure only.

CSS / JS Minifier — How to Use

Remove whitespace and comments from CSS and JavaScript for production.

Paste your CSS or JS source code.
Run the minifier.
Copy the compressed output for deployment.

Tip: Keep original source files — minified code is hard to debug.

Markdown Preview — How to Use

Write Markdown and see formatted HTML output live.

Type Markdown in the editor panel.
View rendered HTML in the preview panel.
Copy HTML or Markdown as needed.

Tip: Preview README files and blog drafts before publishing.

Frequently Asked Questions

Is my code sent to a server?

No. All developer tools execute entirely in your browser. Your JSON, code, and tokens never leave your device.

Can I decode JWT signatures?

The JWT decoder inspects header and payload only. Signature verification requires your secret key and should be done in your backend.

Are the hash algorithms secure for passwords?

Use dedicated password hashing (bcrypt, Argon2) in production. SHA hashes here are for checksums and integrity verification.

Does the regex tester support all flavours?

It uses JavaScript regex syntax. PCRE-specific features may differ slightly from server-side engines.

DEVELOPER / TECH TOOLS