Tools · Developer Tools
JSON Formatter, Validator & Viewer
Format, validate, minify, repair, search and explore JSON directly in the browser.
This JSON is large. Auto-format is off, search is delayed, and highlighting is reduced so the tab stays responsive.
Formatting, validation, repair, and search run in this browser. JSON is not uploaded. API: None.
How to format JSON
- Paste JSON or upload a .json or .txt file from this device.
- Choose 2 spaces, 4 spaces, or tab indent, then format, validate, or minify.
- Use the tree to copy a JavaScript path or JSONPath, or open the fixer if the JSON is invalid.
FAQ
Is my JSON uploaded to a server?
No. Parsing, formatting, validation, repair, and search run in your browser. The file is not uploaded to DevNestro.
Does formatting change my values?
No. Indent and key order (if you sort) can change. String contents, numbers, booleans, and null stay the same. Arrays are never reordered.
What can the JSON fixer repair?
Trailing commas, single quotes, unquoted keys, comments, and missing brackets when the fix is unambiguous. You preview each change. Ambiguous input is not rewritten silently.
How large a file can I format?
The default import limit is 20 MB. Larger files are rejected rather than truncated. Very large JSON disables auto-format and delays search so the tab stays usable.
How do I copy a property path?
Open Tree, expand a node, and copy the JavaScript path such as users[0].name or the JSONPath $.users[0].name.
When is the table view available?
Only when the root value is an array of similar objects. Mixed arrays and nested trees stay in the editor or tree.
Read the original guide: Format, validate, and explore JSON without sending it anywhere.