7 Free Online Tools Every Developer Should Bookmark

As a developer, you keep running into small jobs - format a messy JSON response, test a regex before it goes into production, generate a UUID for a database row, encode a string in Base64. Installing a desktop app for each of these is overkill. Here are 7 free browser tools I use almost every week. They need no signup and no install.

1. JSON Formatter

Paste broken or minified JSON and get it formatted, validated and easy to read, with clear error messages when something is wrong. It saves real debugging time when an API returns a wall of text.

Try the JSON Formatter

2. Regex Tester

Test your regular expressions live with match highlighting and a quick reference. Much faster than running a script just to check whether a pattern matches.

Try the Regex Tester

3. UUID Generator

Generate unique IDs in one click, including bulk generation when you need a whole list for seeding a database or test data.

Try the UUID Generator

4. Base64 Encoder and Decoder

Encode text or decode Base64 strings right in the browser, without pasting sensitive data into a random site or writing a one-off script.

Try the Base64 Encoder and Decoder

5. Contrast Checker

Paste your text and background colors and check the contrast ratio against WCAG accessibility standards, so your UI stays readable for everyone.

Try the Contrast Checker

6. Favicon Generator

Make a favicon for your side project from text or an image in seconds, instead of opening a design tool for a 16 pixel icon.

Try the Favicon Generator

7. Readability Checker

Paste any text - a README, docs, or a blog draft - and get a readability score with plain suggestions to make it easier to understand.

Try the Readability Checker

All seven are free, with no account needed. Bookmark the ones you use, and tell me in the comments which small tool you wish existed - I build one new free tool every week.