Use of multiple different sets of allowed characters in identifiers for entities in your API is also a good way to show you customers that you hate them.. Extr

Use of multiple different sets of allowed characters in identifiers for entities in your API is also a good way to show you customers that you hate them.. Extra bonus points for intermittently using case-insensitive but case-preserving identifiers. Microsoft Azure storage APIs is a prime example of this with 4-5 different sets of identifier restrictions dependening on what you're naming. (Including one that allows any valid C# identifier, for which the documentation conveniently refers to the ECMA specification of C#). Also enabling some special characters like # when creating entities, while knowing that # will be interpreted differently when fetching entities. Such that entities with # in the key cannot be fetched or deleted, but only created. Extra extra, bonus points for retaining # support in the interest of backwards compatibility :)