What is the JSON Formatter & Validator?
Paste messy or minified JSON and get clean, indented, validated output instantly. Everything runs in your browser, so the data you paste never touches a server.
The tool is part of the Calabi free tools hub — a collection of 99+ browser-based utilities for developers, designers, and content creators. Everything runs client-side: your files and data never leave your device.
How to use the JSON Formatter & Validator
- Step 1: Paste your JSON into the input box.
- Step 2: Choose Beautify (indented) or Minify (single line).
- Step 3: Copy the validated output — if it's invalid, you'll see exactly what broke.
The tool updates in real time as you interact with it. No button-clicking required for most tools — results appear instantly.
Example
{"a":1,"b":[2,3]} → pretty-printed with 2-space indent
Privacy & security
The JSON Formatter & Validator is designed with privacy as a hard constraint, not an afterthought:
- No upload: Your data is processed in your browser's JavaScript engine. No HTTP request is made to any server while you use the tool.
- No account required: The tool works instantly — no email, no sign-up, no cookie consent wall.
- No logging: Calabi does not log what you paste, upload, or generate. The server only delivers the HTML/JS page — it never sees your content.
- Open to inspection: Open your browser's network inspector while using the tool. You'll see zero outbound requests related to your data.
This architecture is particularly important for the Developer category of tools, where the inputs often contain sensitive or proprietary information.
Frequently asked questions
Is the JSON Formatter & Validator free?
Yes, completely free with no sign-up. Runs in your browser.
Is it safe to paste sensitive data?
Yes. The JSON Formatter & Validator runs entirely client-side in your browser. Nothing is sent to a server. You can verify this with your browser's network inspector — you'll see zero outbound requests when you use the tool.
Does it work offline?
Once the page is loaded, yes. The tool logic is a self-contained JavaScript bundle with no runtime API calls.
What browsers are supported?
Any modern browser — Chrome, Firefox, Safari, Edge. Internet Explorer is not supported.
About Developer utilities
The JSON Formatter & Validator is part of the Developer utilities category in the Calabi tools hub. Free online JSON formatter and validator. Beautify or minify JSON in your browser — your data never leaves your device. All tools in this category run entirely in your browser with no server involvement.