Format, query & visualize
Pretty-print, validate, repair, sort, run JSONPath and explore data as a collapsible tree or mind map.
Private JSON workspace
JSON formatter, beautifier & validator
Pretty-print JSON, validate it, view a tree, minify, repair and compare payloads in your browser. Convert JSON to XML, CSV, YAML or TOML without sending data to a server.
JSON formatter
Input
Output · preview.json
{ }
Run a tool to see a polished result here
Online JSON formatter, beautifier, validator and viewer
JFmt is a free JSON formatter online — also used as a JSON beautifier, pretty printer, JSON validator and JSON viewer. Paste a payload to format JSON with indentation, check that it is valid JSON, minify it for APIs, repair common syntax errors, or convert JSON to XML, CSV, YAML, TOML, query strings and Postman collections. Processing stays on your device.
34 local tools
A focused toolkit for real JSON work.
Useful operations, clear errors and responsive performance without accounts, uploads or distractions.
Convert every common format
Move between JSON, CSV, XML, YAML, TOML, query strings and Postman collections without uploading data.
Generate production models
Turn JSON and SQL into portable SQL, Java, C#, Go and Dart model definitions in one click.
Tools
Dedicated tool pages
Open beautifier, validator, viewer, minify, converters, and more with the matching tool already selected.
Built for privacy
No upload. No account. No history.
Formatting runs inside a dedicated browser Web Worker. Content is not posted to JFmt, written to cookies or saved unless you enable auto-save.
What is an online JSON formatter or beautifier?
A JSON formatter (also called a JSON beautifier or pretty print) indents objects and arrays so a payload is readable. People also search for a JSON viewer, JSON validator or “format JSON” — JFmt covers those in one local editor, then minifies or repairs trailing commas and single quotes.
Can I convert JSON to XML, CSV or YAML?
Yes. Conversion is local in the same tab: JSON with XML, CSV, YAML, TOML, query strings and Postman collections. Nothing is posted to jfmt.dev.
Can I format sensitive JSON?
Processing is local, but you should still remove secrets before sharing screenshots or copied output with other services.
Does it support large files?
The Web Worker keeps parsing away from the interface. Practical limits still depend on your browser and device memory.
What does repair change?
Repair targets syntax, not meaning. Always review repaired output before using it in production systems.