JSON Formatter & Validator

Paste it in, get the answer instantly — nothing leaves your browser.

🔒 Everything is processed by your own browser. What you paste is never uploaded, stored, or sent anywhere.

About this tool

JSON Formatter & Validator does one job and does it in your browser. There is no account to create, no queue to wait in and no upload — the work happens on your own device using ordinary browser APIs.

Paste your content into the box above, or drop a file onto it, and it is processed immediately. Up to 5 MB works comfortably; the limit comes from your device's memory rather than from a server.

Running locally is not just a technical detail. Most online tools send what you give them to a server, process it there, and ask you to trust that it is deleted afterwards. Here the content never leaves your computer, which means sensitive data never has to leave your control, and the tool keeps working even if your connection drops.

The tool is free and paid for by advertising. There is no paid tier, no features behind a login and nothing to sell on — what you enter never reaches us in the first place. If you decline ads, the tool behaves exactly the same.

How it works

1. Paste into the box above, or drop a file onto it.
2. Press the button — everything runs immediately, on your device.
3. Copy the result, or download it as a file.

What people use it for

• Quickly inspect the contents of a file somebody sent you.
• Work with material that must not leave your machine — nothing is ever uploaded.
• Avoid installing an application for a task you do a few times a year.
• Arrive from a search for "json validator" and finish the job on the spot.
• Arrive from a search for "json formatter" and finish the job on the spot.

Frequently asked questions