Question 1

Why can't I add comments to my JSON file?

Accepted Answer

JSON was designed for data exchange between systems, not as a configuration format. Douglas Crockford, who created JSON, intentionally excluded comments to keep the format simple and prevent misuse. For config files that need comments, consider using JSON5 or JSONC, which extend JSON with comment support. Some tools like VS Code treat .jsonc files specially.

Question 2

What is the maximum size limit for JSON?

Accepted Answer

JSON itself has no size limit, but the systems processing it do. JavaScript engines typically handle JSON up to a few hundred megabytes. APIs often limit request/response size to 1-10MB. For very large datasets, consider streaming parsers, pagination, or binary formats like Protocol Buffers or MessagePack.

Question 3

How do I handle dates in JSON?

Accepted Answer

JSON has no native date type, so dates are stored as strings. The ISO 8601 format (2024-01-15T10:30:00Z) is the standard choice because it sorts correctly and is unambiguous about timezone. When parsing, you will need to convert these strings back to date objects in your programming language.

Question 4

What is the difference between JSON and JavaScript objects?

Accepted Answer

JSON is a text format, JavaScript objects are in-memory data structures. JSON requires double quotes around all keys and strings. JavaScript objects allow single quotes, unquoted keys, and additional features like functions, undefined, and trailing commas. JSON.parse() converts JSON text to a JavaScript object, JSON.stringify() does the reverse.

Question 5

Why does my JSON have Unicode escape sequences like \u0027?

Accepted Answer

Some JSON encoders escape non-ASCII characters for maximum compatibility. The sequence \u0027 represents an apostrophe. This is valid JSON and will decode correctly. You can usually configure your encoder to output UTF-8 directly instead of escape sequences, which makes the JSON more readable.

Question 6

How do I pretty print JSON in the browser console?

Accepted Answer

Use JSON.stringify(yourObject, null, 2) where the third argument sets the indentation. The 2 means two spaces per level. You can also use console.dir(yourObject) for an interactive tree view in most browsers. Chrome DevTools has a JSON viewer for network responses that formats automatically.

Question 7

Can JSON keys be duplicated?

Accepted Answer

Technically the JSON specification allows duplicate keys, but behavior is undefined. Most parsers will use the last value when duplicates exist. This can cause bugs and confusion. Always treat keys as unique. Linters and validators can warn you about duplicate keys.

Question 8

jsonFormatter.faq.q8.question

Accepted Answer

jsonFormatter.faq.q8.answer

JSON Formatter

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