Free Online Developer Tools
JSON formatter, URL encoder, UUID generator, and more — essential dev utilities that run in your browser. 7 tools, all free.
JSON Formatter
Format, beautify, minify, and validate JSON instantly. Catch syntax errors with line numbers.
Use tool →URL Encoder/Decoder
Encode or decode URLs and special characters. Supports component and full URL encoding.
Use tool →UUID Generator
Generate random UUID v4 identifiers. Bulk generate, multiple formats, copy with one click.
Use tool →Timestamp Converter
Convert Unix timestamps to dates and vice versa. Supports seconds, milliseconds, and ISO 8601.
Use tool →Escape/Unescape HTML
Escape or unescape HTML entities. Convert special characters for safe embedding in web pages.
Use tool →Regex Tester
Test regular expressions in real-time with match highlighting, capture groups, and a quick reference.
Use tool →Text Diff Tool
Compare two texts side-by-side or inline. See additions, deletions, and unchanged lines at a glance.
Use tool →Browser-Based Developer Tools — No Installs Required
SmarterSources offers a curated set of developer utilities that run entirely in your browser. There is nothing to install, no accounts to create, and no data sent to any server. Whether you are debugging a JSON response at your desk or encoding a URL from your phone, these tools are ready the moment you need them.
Why Use Browser-Based Dev Tools?
Traditional developer tools often require installing desktop apps, configuring environments, or trusting third-party servers with your data. Browser-based tools eliminate all of that. They work on any device with a modern browser — Windows, Mac, Linux, even tablets. Everything runs client-side using JavaScript, so your code snippets, JSON payloads, and URLs never leave your machine. They are perfect for quick tasks when you do not want to spin up a terminal or search through CLI documentation.
What Each Tool Does
The JSON Formatter takes raw or minified JSON and formats it with proper indentation for easy reading. It also validates your JSON and highlights syntax errors with line numbers, saving you from hunting through hundreds of lines for a missing comma. The URL Encoder/Decoder handles percent-encoding for URLs and query strings, supporting both full URL and component-level encoding — essential when building API requests or debugging query parameters.
The UUID Generator creates cryptographically random UUID v4 identifiers on the fly. Generate one or bulk-generate hundreds at once, then copy them in standard, uppercase, or no-dash formats. The Timestamp Converter translates between Unix timestamps and human-readable dates, handling seconds, milliseconds, and ISO 8601 formats. It is invaluable when working with APIs, logs, or databases that store dates as epoch values.
Finally, the Escape/Unescape HTML tool converts characters like <, >, &, and " into their HTML entity equivalents and back. Use it to safely embed user-generated content in web pages or to decode escaped HTML from API responses.
Frequently Asked Questions
Is my data safe when using these developer tools?
Yes. All processing happens locally in your browser using JavaScript. Your JSON data, URLs, and other inputs are never transmitted to any server. You can verify this by using the tools with your network disconnected — they work entirely offline.
Do these tools work on mobile devices?
Yes. Every tool is fully responsive and works on phones and tablets. While a desktop or laptop is more comfortable for heavy development work, these tools are handy for quick lookups and conversions on the go.
What is the difference between URL encoding and component encoding?
Full URL encoding (encodeURI) encodes special characters but leaves characters like /, :, and ? intact so the URL structure is preserved. Component encoding (encodeURIComponent) encodes everything except letters, digits, and a few safe characters — use it for individual query parameter values where slashes and colons should be escaped.
What is a UUID and when should I use one?
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as a 36-character string like 550e8400-e29b-41d4-a716-446655440000. Version 4 UUIDs are randomly generated and have an astronomically low chance of collision. They are commonly used as database primary keys, session tokens, tracking IDs, and anywhere you need a unique identifier without a centralized counter.