JSON Formatting and Validation Guide

JSON (JavaScript Object Notation) is the most common format for APIs and config files. It is simple, but small mistakes break it entirely. Here is how to keep yours valid.

The most common JSON errors

• Trailing commas — a comma after the last item in an array or object is invalid.
• Single quotes — JSON strings must use double quotes.
• Unquoted keys — every key needs double quotes.
• Missing brackets — every { and [ needs a matching } and ].

Pretty-print vs minify

Pretty-printing adds indentation so JSON is readable while debugging. Minifying strips whitespace to make payloads smaller for transport. Use the JSON formatter to switch between both.

Debugging an API response

Paste the raw response into a validator. If it errors, the position usually points near the real problem — often a stray comma or an unescaped quote inside a string.