SparkJSON

SparkJSONOnline JSON Viewer

Online JSON Viewer

SparkJSON’s online JSON viewer helps you read nested API responses and config files without fighting minified one-liners. Beautify for scanning, validate for safety, and keep everything on your device — nothing is uploaded.

Free SparkJSON tool — runs 100% in your browser. No signup, no upload, no paywall. This page opens in format / beautify mode.

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JSON viewer vs formatter

A JSON viewer is optimized for reading structure: indentation, nesting, and spotting missing fields. SparkJSON combines viewer-friendly formatting with a validator so broken documents don’t look “almost right.”

Use the side-by-side input/output layout to compare raw paste vs formatted result, then copy only what you need.

  • Readable layout — line numbers and consistent indentation.
  • Inspect safely — invalid JSON is labeled with location details.
  • No cloud sync — close the tab and the data is gone from memory.

Frequently asked questions

Can I view JSON files from disk?
Yes. Use Upload to load a .json file into the editor. The file is read locally in your browser and never sent to SparkJSON servers.
Is this a collapsible tree viewer?
SparkJSON focuses on formatted text with validation. For tree UIs you can still beautify here first, then paste into a specialized tree viewer if needed.