DataDesignTools

About DataDesignTools

A free, fast suite of developer tools that run entirely in your browser. No sign-up, no server uploads, no cost — just open and use.

100% FreeBrowser-basedNo sign-upNo data sent to serversOpen instantly

Our Mission

Developers spend a significant amount of time on repetitive data tasks — formatting JSON, writing JSONPath queries, comparing API responses, encoding strings. These tasks shouldn't require installing software, signing up for a service, or waiting for a page to load.

DataDesignTools was built to be the go-to browser bookmark for these everyday developer tasks. Every tool is instant, works offline after first load, and never touches your data outside of your own browser tab.

Tools Available

{ }

JSON Formatter

Format, minify, sort keys, repair broken JSON, and visualise with a collapsible tree.

JSONPath Evaluator

Run JSONPath expressions against any JSON document. Results update live as you type.

⇆

JSON Diff

Compare two JSON documents side-by-side with colour-coded added, removed and changed lines.

◎

JSON → TOON

Convert JSON to Token-Optimised Object Notation and save 30–60% on LLM token usage.

↕

Escape / Stringify

Escape, unescape, stringify and parse JSON strings with a live character diff.

Base64 Encoder

Encode and decode Base64 and URL-safe Base64 with full Unicode support.

Gzip ⇄ Text

Compress text to gzip (Base64 / Hex) or decompress gzip data and .gz files back to text.

⬡

SQL Formatter

Format, minify and syntax-highlight SQL queries with keyword case conversion.

</>

HTML Preview

Live sandboxed HTML preview at desktop, tablet and mobile viewport sizes.

Privacy & Data

All processing happens in your browser using JavaScript. When you paste a JSON document, type a SQL query, or enter text to encode, that data never leaves your device. We have no servers that receive or store your tool input.

We use Google Analytics to understand aggregate usage (which tools are popular, what browsers people use) and Google AdSense to display ads that keep the site free. Both services may set cookies. See our for full details.

Contact

Have a suggestion, found a bug, or want to request a new tool? We'd love to hear from you.

Email: hello@datadesigntools.com