How to Fix Common JSON Syntax Errors
JSON errors are usually caused by a small set of syntax problems. Learn how to find trailing commas, missing quotes, mismatched brackets, and invalid escapes before debugging application code.
Start with the parser error
When a JSON parser reports a position, inspect the character immediately before and around that location. The reported location can be where the parser realized the structure was impossible, not necessarily where the original mistake began.
Check the four common problems
JSON requires double-quoted property names and strings, commas between array/object elements, matching `{}` and `[]`, and no trailing comma after the final member.
Use the validator before the formatter
A formatter cannot make invalid JSON valid. Run the JSON Validator first when parsing fails, then use the Formatter or Beautifier after the syntax is corrected.
Keep JSON strict
JavaScript object literals can contain comments, single-quoted strings, and trailing commas, but standard JSON cannot. Copying a JavaScript object literal directly into a JSON API payload often causes errors.