Free Online Developer Tools
The JSON Formatter validates syntax and pretty-prints with configurable indentation, with inline error highlighting when the input is invalid. The Base64 Encoder and Decoder handles plain text, HTML, CSS, SQL, and arbitrary binary data. The Regex Tester shows real-time match highlighting with g, i, and m flag toggles plus capture group display in a results panel. The CSS Gradient Generator produces linear, radial, and conic gradients with any number of colour stops and exports ready-to-paste CSS.
Newer additions include the Text Diff Checker (using an LCS algorithm, the same approach as git diff), the Text Case Converter with 8 output formats including camelCase, PascalCase, and snake_case, and a live UNIX Timestamp Converter that shows the current timestamp and converts between seconds, milliseconds, and human-readable dates in multiple timezones.
15 Free Free Online Developer Tools
Word & Character Counter
Count words, characters, sentences and reading time. Essential for bloggers, copywriters and SEO con…
→Secure Password Generator
Generate strong random passwords with custom length, uppercase, numbers and symbols. Uses cryptograp…
→CSS Gradient Generator
Create beautiful CSS linear and radial gradients with a live visual picker. Copy the ready-to-use CS…
→Base64 Encoder & Decoder
Encode text to Base64 and decode Base64 strings back to plain text. Essential for web developers and…
→JSON Formatter & Validator
Format, beautify and validate JSON data online. Minify JSON and highlight syntax errors with clear m…
→Meta Tag Generator
Generate SEO title tags, meta descriptions and Open Graph tags for any web page. Copy-ready HTML out…
→Hashtag Generator
Generate targeted hashtags for Instagram, Twitter and LinkedIn from design, marketing, business and …
→Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences or words. Start with classic Lorem ipsum or use r…
→Color Code Converter
Convert between HEX, RGB and HSL color formats instantly. Click any result to copy to clipboard.
→URL Encoder & Decoder
Encode special characters in URLs for safe transmission. Decode URL-encoded strings back to readable…
→Text Diff Checker
Compare two texts side-by-side and highlight every addition, deletion and change between them.
→Regex Tester
Test regular expressions against any string. See matches highlighted in real time with capture group…
→Slug Generator
Convert any text into a clean, SEO-friendly URL slug. Removes special characters and formats with hy…
→Text Case Converter
Convert text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case and keba…
→Timestamp Converter
Convert UNIX timestamps to human-readable dates and back. Show current timestamp in seconds and mill…
Guides and Articles
Favicon Size Guide: What Size Should Your Favicon Be in 2026?
The complete guide to favicon sizes — what dimensions you need, which formats to use, and how to generate them all at once.
Free Favicon Generator — Create Website Favicons in All Sizes
Generate all required favicon sizes from any image online — 16x16 to 512x512 pixels. Download ICO, PNG and SVG formats instantly. …
Meta Tags for SEO — Complete Guide with Examples (2026)
Learn how to write title tags, meta descriptions, and Open Graph tags for better SEO and social media sharing. Includes examples a…
Best Free Web Design Tools in 2026 — No Subscription Needed
The best free web design tools in 2026 — CSS generators, color tools, favicon makers, image optimisers, and developer utilities. A…
JSON Formatting and Validation: A Complete Developer Guide
JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. Every REST API, most configuration f…
CSS Gradients: Complete Guide with Types, Examples and a Free Generator
CSS gradients let you create smooth transitions between two or more colours without using image files. They are resolution-indepen…
How to Create Strong Passwords in 2026 — Length, Rules and Best Practices
Password security advice has evolved significantly over the past five years. Rules that were standard in 2015 — mixing uppercase, …
URL Encoding Explained: What It Is, Why It Matters, and When to Use It
URLs can only contain a specific set of characters. Everything else must be converted into a safe format before it can be sent as …
Base64 Encoding and Decoding: What It Is and When Developers Use It
Base64 is a binary-to-text encoding scheme that converts arbitrary data — images, audio, documents — into a string of printable AS…
Frequently Asked Questions
Do these tools work offline after the page has loaded?
Yes. Once the page loads, most developer tools require no further network connection — they use no external APIs. The JSON Formatter, Base64 Encoder, Regex Tester, CSS Gradient Generator, URL Encoder, Text Diff Checker, Slug Generator, Text Case Converter, and Timestamp Converter all run entirely in JavaScript with no network requests after the initial page load.
Is it safe to paste sensitive data like API keys or tokens?
Yes. All data is processed in your browser memory and never sent to any server. This makes it safe to paste JSON responses containing authentication tokens, internal configuration values, or private user data for debugging or formatting purposes.
What regular expression syntax does the Regex Tester use?
JavaScript ECMAScript regular expression syntax, which covers character classes, quantifiers, groups, lookaheads, and backreferences. Minor differences exist from PCRE used in Python and PHP — notably lookbehind support varies by browser. Test your pattern in the target language before using in production.
What text case formats does the Text Case Converter support?
UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case. All eight formats are generated simultaneously from a single input, so you can copy whichever format you need without running the tool multiple times.
How does the Text Diff Checker compare to a simple find-and-replace?
The Text Diff Checker uses the Longest Common Subsequence algorithm — the same method used by Git — to identify the minimal set of changes between two text versions. It shows added text in green and removed text in red at the character level, making it accurate for comparing code, article drafts, or configuration files where small changes matter.
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