What is JSON? How to verify and troubleshoot common errors

What is JSON

JSON (JavaScript Object Notation) is a text format commonly used for data exchange between configuration files, API requests and systems. It's easy to read, but the format is very strict: one less comma or one more quote will cause parsing to fail.

Core structure

JSON consists of objects, arrays and basic values. Objects are enclosed in curly brackets, key names must use double quotes; arrays are enclosed in square brackets. Valid JSON can contain strings, numbers, Boolean values, null, objects, and arrays.

{ "user": { "name": "Lin", "active": true }, "tags": ["api", "docs"] }

The most common validation errors

• Use single quotes, or forget to add double quotes for key names.
• There is an extra comma after the last item.
• There are unescaped newlines or double quotes in the string.
• Write JavaScript's undefined, annotations or functions into JSON.

Practical troubleshooting sequence

First, let the formatter/validator locate the error line, and then check the paired structure from the outer curly bracket or square bracket inwards. After confirming that the format is valid, check the field names, types, and business rules; these three things should not be mixed together.

Conclusion

JSON verification is the first threshold for data quality. Correct format does not mean that the data must meet the requirements, but if the format is incorrect, subsequent verification will not start at all.