The JSON syntax does not impose any restrictions on the strings used as names,... There is no standard naming of keys in JSON and that camelCase or snake_case should work fine.

Is JSON snake case or camelCase?

Languages Using JSON

It basically follows the logic that you consider the languages being used to generate or parse the JSON. It makes the case that Python and PHP favor snake case, whereas Java and JavaScript favor camel case.

When should camelCase be used?

Software developers often use camelCase when writing source code. camelCase is useful in programming since element names cannot contain spaces. The camelCase naming convention makes compound names more readable. For example, myOneMethod is easier to read than myonemethod.