Which characters are valid/invalid in a JSON key name?

Are there any forbidden characters in key names, for JavaScript objects or JSON strings? Or characters that need to be escaped?

To be more specific, I'd like to use "$", "-" and space in key names.



No. Any valid string is a valid key. It can even have " as long as you escape it:

{"The \"meaning\" of life":42}

There is perhaps a chance you'll encounter difficulties loading such values into some languages, which try to associate keys with object field names. I don't know of any such cases, however.


It is worth mentioning that while starting the keys with numbers is valid, it could cause some unintended issues.


var testObject = {
    "1tile": "test value"
console.log(testObject.1tile); // fails, invalid syntax
console.log(testObject["1tile"]; // workaround

Unicode codepoints U+D800 to U+DFFF must be avoided: they are invalid in Unicode because they are reserved for UTF-16 surrogate pairs. Some JSON encoders/decoders will replace them with U+FFFD. See for example how the Go language and its JSON library deals with them.

So avoid "\uD800" to "\uDFFF" alone (not in surrogate pairs).


Following characters must be escaped in JSON data to avoid any problems

‘ single quote

” quote

\ backslash

all control characters like \n \t

JSON Parser can help you to deal with JSON.

EDIT: Here's a replacement JSON parser since OP's link is dead


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