JSON Viewer – Format, Validate & Explore JSON Online
About JSON Viewer
Paste, drop, or open a JSON file to instantly pretty-print it, check that it is valid, and browse the structure as a collapsible tree — all in your browser, with nothing sent to a server.
A JSON viewer turns a wall of minified text into something you can actually read. ToolsNest formats (beautifies) JSON with proper indentation, flags syntax errors with the exact line and column, and renders objects and arrays as an expandable tree so you can drill into deeply nested data without losing your place.
Because every step runs locally in your browser, you can safely inspect API responses, config files, logs, and exports that contain keys, tokens, or personal data — none of it is uploaded, stored, or logged. It also handles large files that would choke an online editor that round-trips to a server.
What you can use it for
- Debug an API response — paste the payload, expand the tree, and find the field you need.
- Fix invalid JSON — see the precise line and column of a missing comma or bracket.
- Clean up a config file before committing — beautify it with consistent indentation.
- Shrink JSON for a request body or environment variable — minify it to a single line.
- Read an unfamiliar export or webhook payload without hunting through minified text.
How it works, step by step
- 1
Add your JSON
Paste JSON into the editor, drag a .json file onto the page, or click Load JSON data to open one from your device.
- 2
Format or minify
Click Format to pretty-print with indentation, or Remove white space to minify it to one line.
- 3
Check it is valid
Invalid JSON is highlighted with the exact line and column, so you can fix syntax errors fast.
- 4
Explore the tree
Switch to the Viewer tab and expand or collapse objects and arrays to inspect nested values.
- 5
Copy the result
Use Copy to grab the formatted or minified output — nothing ever leaves your browser.
Frequently asked questions
Is this JSON viewer free?
Yes. Every feature — formatting, validation, minifying, and the tree view — is free with no sign-up and no limits.
Is my JSON uploaded anywhere?
No. All parsing and formatting happens locally in your browser. Your data is never sent to a server, stored, or logged, so it is safe for payloads that contain tokens or personal information.
How do I parse JSON online?
Paste your JSON into the editor. It is parsed instantly — if it is valid you will see a formatted tree; if not, the error is shown with its line and column.
Can it handle large JSON files?
Yes. Because there is no server round-trip, it comfortably handles large files that time out on upload-based tools. Very large files (tens of MB) depend on your device's memory.
What is the difference between formatting and minifying JSON?
Formatting (beautifying) adds indentation and line breaks so JSON is easy to read. Minifying removes all whitespace to make it as small as possible for storage or transport.
Does it validate JSON against a schema?
It validates JSON syntax — brackets, quotes, commas, and value types. JSON Schema validation is not included.