100% in your browser · files never leave your device

JSON Viewer & Formatter — Free & Private (In-Browser)

Paste or upload JSON to format, validate, and browse it as a collapsible tree. Runs 100% in your browser — your data is never uploaded.

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Pretty-print JSON without pasting it into a random viewer

API dumps and config files can contain tokens. Paste here if you would not paste there. Formatting runs in the tab. We do not log the document.

This is not a linter-as-a-service and not a schema host. Invalid JSON fails locally with the parser message and position. That is expected.

Use the collapsible tree to browse, formatted text to copy back into a file, and minify when you need a single line. Large documents are limited by RAM in the tab.

How to use JSON Viewer

  1. 1Paste JSON into the input, or upload a .json file.
  2. 2Invalid JSON shows a clear error with the parser message.
  3. 3Browse it as a collapsible tree or as formatted text; pick indent.
  4. 4Copy minified/beautified JSON or download the formatted file.

JSON Viewer FAQ

Is my JSON uploaded anywhere?
No. Parsing and formatting happen in this tab. Paste here if you would not paste an API dump into a random viewer — tokens stay on the device.
Will it tell me if my JSON is invalid?
Yes. The viewer reports the parser message and position. This is not a schema host and not a linter-as-a-service. Invalid JSON fails locally; that is expected.
Tree view or formatted text — which should I use?
The collapsible tree is for browsing nested objects. Formatted text is for copy-paste back into a file. Pick the indent before you copy. You can also minify.
Can I open a .json file instead of pasting?
Yes. The file is read locally. Large documents are limited by RAM in the tab, not by an upload quota.

Updated 26 August 2026

What is JSON Viewer?

Paste or upload JSON to format, validate, and browse it as a collapsible tree. Runs 100% in your browser — your data is never uploaded.

  • Paste or open a .json file; invalid input shows the parser message and position.
  • Switch the collapsible tree and the formatted text; pick the indent.
  • Tokens in an API dump stay in this tab. We do not log the document.

How to use it

  1. Paste JSON into the input, or upload a .json file.
  2. Invalid JSON shows a clear error with the parser message.
  3. Browse it as a collapsible tree or as formatted text; pick indent.
  4. Copy minified/beautified JSON or download the formatted file.