Free Online Developer Tools

Free Online Developer Tools That Run in Your Browser

ToolRux offers 26 free developer tools built for speed, privacy, and convenience. Format JSON, test regex patterns, generate hashes, compare diffs, convert encodings, build cron expressions, and more — all without installing anything or sending data to a server.

Data & Code Formatting

Parse, validate, and format your data with instant feedback:

• JSON Formatter — Format, validate, minify, and explore JSON data with syntax highlighting, error detection, and a collapsible tree view. Handles large payloads and shows precise error locations.
• Diff Checker — Compare two blocks of text side by side with additions, deletions, and changes highlighted line by line. Perfect for reviewing config changes, code diffs, or content edits.
• Text Case Converter — Convert text between 12 formats: UPPER CASE, lower case, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, path/case, and more.
• SQL Formatter — Format and beautify SQL queries with proper indentation, keyword highlighting, and support for multiple SQL dialects.
• HTML Formatter — Format and beautify HTML markup with proper indentation and tag alignment for cleaner, more readable code.
• Code Minifier — Minify HTML, CSS, and JavaScript code to reduce file size for production deployment.
• JSON Schema Validator — Validate JSON data against a JSON Schema definition with detailed error reporting.

Pattern Matching & Testing

Debug and validate patterns in real time:

• Regex Tester — Test regular expressions with real-time match highlighting, capture group extraction, flag toggles (global, case-insensitive, multiline), and a library of common patterns (email, URL, IP address, dates, and more).
• Cron Expression Generator — Build and decode cron expressions visually. See human-readable descriptions and the next scheduled run times. Supports standard 5-field cron syntax with presets for common schedules.

Encoding & Hashing

Securely encode, decode, and hash data entirely in your browser:

• Base64 Encoder / Decoder — Encode text to Base64 or decode Base64 back to plain text. Useful for embedding data in URLs, APIs, and configuration files.
• URL Encoder / Decoder — Encode special characters for URLs or decode percent-encoded strings back to readable text. Essential for working with query strings and API parameters.
• Hash Generator — Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from any text input using the Web Crypto API. Compare hashes for integrity verification.
• Password Generator — Generate cryptographically secure random passwords with custom length, character sets (uppercase, lowercase, numbers, symbols), and a visual strength meter with entropy calculation.
• HTML Entity Encoder / Decoder — Encode special characters to HTML entities or decode entities back to readable text. Essential for safe HTML output.

Generators & Utilities

• Lorem Ipsum Generator — Generate placeholder text in paragraphs, sentences, or words for mockups and prototypes.
• UUID / GUID Generator — Generate RFC 4122 compliant UUIDs (v4) instantly. Bulk generate multiple UUIDs at once.
• Markdown Editor — Write and preview Markdown in real time with syntax highlighting, formatting toolbar, and HTML export.
• API Response Tester — Test REST API endpoints with GET, POST, PUT, and DELETE methods. View response headers, status codes, and body.
• Webhook Tester — Inspect and debug webhook payloads with a live request viewer and response configurator.

Number & Character Systems

Convert between number bases and character encodings:

• ASCII / Unicode Converter — Convert text to ASCII/Unicode code points (decimal, hex, binary) and back. Browse the full ASCII table with search and filtering.
• Number Base Converter — Convert between binary, decimal, hexadecimal, and octal instantly. All four bases displayed simultaneously with bit-length information.

Color & Visual Tools

• Color Converter — Convert between HEX, RGB, and HSL color formats with live preview, ready-to-use CSS snippets, and a WCAG contrast checker for accessibility compliance.
• CSS Gradient Generator — Create beautiful linear and radial CSS gradients with a visual color-stop editor and instant CSS output ready to copy.
• Data Visualizer / Chart Maker — Paste CSV, TSV, or JSON data and instantly generate bar, line, pie, doughnut, or horizontal-bar charts. Customize colors, labels, and dimensions, then export as PNG or SVG.

Accessibility & Testing

• WCAG Accessibility Checker — Paste any HTML and instantly audit it against 15 WCAG 2.1 AA rules including image alt text, heading order, color contrast, ARIA roles, landmark uniqueness, and more. Get severity ratings with actionable fix suggestions.

Time & Scheduling

• Epoch / Unix Timestamp Converter — Convert between Unix timestamps and human-readable dates. Supports seconds and milliseconds, with live clock display and common timestamp shortcuts.

Need unit or currency conversions? Check out our Converter Tools. For visual design work, see our Design Tools.

Why Use ToolRux Developer Tools?

• 100% Browser-Based — All processing happens locally. Your code and data never leave your device.
• No Installation — No extensions, plugins, or CLI tools to install. Just open and use.
• Free Forever — Every developer tool is completely free with no account required.
• Shareable URLs — Tool settings are saved in the URL so you can share or bookmark your exact configuration.
• Dark Mode — Easy on the eyes with automatic dark mode support across all tools.
• Mobile Ready — Fully responsive design works on phones, tablets, and desktops.

Frequently Asked Questions

Are my data and code safe when using these tools?

Yes. All ToolRux developer tools process data entirely in your browser using JavaScript and the Web Crypto API. Nothing is sent to any server. Your code, JSON, regex patterns, and passwords never leave your device.

Do I need to create an account?

No. Every tool is free to use instantly — no sign-up, no login, no restrictions.

What JSON features does the formatter support?

The JSON Formatter validates, formats (pretty-print with custom indent), minifies, and provides a collapsible tree view with syntax highlighting. It shows precise error messages with line numbers for invalid JSON.

What regex flavors does the tester support?

The Regex Tester uses JavaScript's built-in RegExp engine, supporting flags like global (g), case-insensitive (i), multiline (m), dotAll (s), and Unicode (u). It includes a library of common patterns you can load with one click.

How secure are the generated passwords?

Passwords are generated using the Web Crypto API (crypto.getRandomValues()), which provides cryptographically secure random numbers. The strength meter shows entropy in bits — aim for 80+ bits for strong passwords.

What hash algorithms are supported?

The Hash Generator supports SHA-1, SHA-256, SHA-384, and SHA-512 via the Web Crypto API. All hashing is performed locally in your browser.

Can I use the cron generator for non-standard cron formats?

The Cron Expression Generator supports standard 5-field cron syntax (minute, hour, day-of-month, month, day-of-week) used by most Unix-like systems, Kubernetes, and CI/CD platforms. It shows the next scheduled run times for verification.

What color formats does the color converter support?

The Color Converter supports HEX (3/6/8-digit), RGB, and HSL formats with live preview. It also includes a WCAG contrast ratio checker to verify text accessibility against any background color.

Can I share my tool results with someone?

Yes. Most developer tools save their settings in the URL. Simply copy the URL from your browser address bar and share it — the recipient will see the exact same configuration and results.

What does the WCAG Accessibility Checker test?

The WCAG Checker audits HTML against 15 WCAG 2.1 Level AA rules covering image alt text, heading order, color contrast (4.5:1 ratio), form labels, ARIA roles, landmark uniqueness, link/button names, and more. All checks run client-side using DOMParser.

What chart types does the Data Visualizer support?

The Data Visualizer supports bar, line, pie, doughnut, and horizontal-bar charts. Paste CSV, TSV, or JSON data to generate a chart instantly, then customize colors, dimensions, and labels before exporting as PNG or SVG.

Do the tools work offline?

Most tools work offline once the page is loaded, since all processing is client-side. However, the initial page load requires an internet connection.