ToolKit

Developer Tools

Free Online Developer Tools

A collection of browser-based utilities for everyday development tasks. Format JSON, encode Base64, generate UUIDs, test regex patterns, convert timestamps, and more — all running locally in your browser with no data sent to any server.

UUID Generator
Generate v4 UUIDs instantly
Live
Base64 Encoder / Decoder
Encode or decode Base64 strings instantly
Live
JSON Formatter
Prettify, minify & validate JSON
Live
URL Encoder / Decoder
Encode and decode URLs instantly
Live
Regex Tester
Test and debug regular expressions live
Live
Timestamp Converter
Convert Unix timestamps to human-readable dates
Soon
Cron Expression Generator
Build and validate cron job schedules
Soon
CSS Minifier
Minify and beautify CSS code
Soon
HTML Entities Encoder
Encode and decode HTML entities
Soon

Tools developers use every day

Every tool in this category targets a specific, recurring task in a development workflow. They are not feature-heavy applications — they solve one problem quickly and get out of your way. The MDN Web Docs are the reference for the browser APIs used here.

All tools use native browser APIs — no external libraries are loaded for the core functionality. The JSON Formatter uses JSON.parse() and JSON.stringify(). The UUID Generator uses crypto.randomUUID(). The Base64 tool uses btoa() and atob(). What runs in the tool runs identically in your code.

Which tool do you need?

JSON Formatter
Debugging API responses, reading config files, validating JSON before sending a request.
Base64 Encoder
Working with data URIs, HTTP Basic Auth headers, JWT tokens, or MIME email attachments.
UUID Generator
Generating database primary keys, API resource IDs, session tokens, or idempotency keys.
URL Encoder
Building query strings, encoding special characters in URLs, debugging redirect parameters.
Regex Tester
Validating patterns before adding to code, testing email/URL/date regex, debugging capture groups.
Timestamp Converter
Converting Unix epoch timestamps to human-readable dates and back. Essential for log analysis.

FAQ

Common questions

What is the most useful developer tool on this page?

It depends on your daily workflow. JSON Formatter is the most universally used — almost every developer works with JSON APIs. Base64 Encoder is essential for working with data URIs and authentication headers. Regex Tester is invaluable for anyone working with text processing or log parsing.

Do these tools work offline?

All tools run entirely in your browser with no server calls for the core functionality. Once the page is loaded, the tool logic works without an internet connection. The only exception is if your browser needs to load fonts or other static assets.

What is the difference between URL encoding and Base64 encoding?

URL encoding (percent-encoding) makes text safe for use in URLs by replacing special characters with %XX sequences. Base64 encoding converts binary data to ASCII text for transmission through text-only channels. URL encoding is for URLs; Base64 is for binary data transport in emails, JWTs, and data URIs.

Why does my JSON have a syntax error?

The most common JSON errors are: trailing commas after the last property (not allowed in JSON), single quotes instead of double quotes, unquoted property keys, and undefined or NaN values (not valid JSON types). Use the JSON Formatter's Validate mode to get a specific error message.

When should I use a UUID as a database primary key?

Use UUIDs when you need to generate IDs across distributed systems without coordination, when you want to avoid leaking sequential IDs in public APIs, or when merging data from multiple databases. The tradeoff is larger storage size and slightly slower index performance compared to integer IDs.

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