JSON Formatter
Indent JSON so you can read it, or squeeze it onto one line. Syntax errors are reported with the line they are on.
Result
How to use
Paste JSON into the box on the left and the formatted result appears on the right. An API response copied straight out of the network tab works fine.
Indentation can be two or four spaces. The minify button strips it all out, which is what you want before sending JSON over the wire.
When the syntax is wrong you get the line and column of the problem along with a message. A missing comma or an unbalanced quote is quick to find that way.
Nothing you paste is sent to a server. It is processed inside your browser, so JSON containing internal data is safe to work with here.