JSON has no tolerance for a trailing comma, an unquoted key, or a stray single quote - and the error a browser console gives you for a broken payload ("Unexpected token") rarely points at the actual problem. This formats, validates, and minifies JSON, with a collapsible tree view for digging into deeply nested API responses, plus conversion to XML, YAML and CSV.

When you'd use this

Debugging an API response that arrived as one unreadable line - paste it in, get properly indented output you can actually scan, or switch to the tree view to collapse everything except the branch you care about.

Converting between formats: a YAML config that needs to become JSON for a script, or a JSON array that needs to land in a spreadsheet as CSV.

Common errors

The most frequent validation failure is a trailing comma after the last item in an object or array - valid in JavaScript object literals, invalid in strict JSON. Unquoted keys and single-quoted strings are the next two most common, both also valid JS but not valid JSON.

If a value looks like a number but is being treated as a string (or vice versa) after a round trip through YAML or CSV, check for a leading zero or a value like "NA" - different formats infer types differently, and this converter doesn't force a coercion it isn't confident about.

Frequently asked questions