How to Format JSON and Find Common Syntax Errors

Rules for valid JSON

Property names and strings use double quotes. Objects and arrays cannot have a trailing comma. Boolean values and null are lowercase. Comments are not part of standard JSON.

Format before debugging

Paste the content into the formatter. Valid JSON receives consistent indentation. Invalid JSON normally returns a character position; inspect the nearby comma, quote, brace, or bracket and then retry.

Protect sensitive API data

API responses can contain tokens, email addresses, customer records, or internal endpoints. Local processing reduces server exposure, but you should still consider browser extensions, shared computers, and clipboard history.

Handling very large JSON

Large payloads consume memory and can make the page slow. Remove unnecessary fields, inspect smaller sections, or use a streaming parser in a development environment.