Should an API strip whitespace in user content?

Question

Let’s say there is a REST API which allows users to create objects. These objects have a name. The name doesn’t need to be unique among all objects and doesn’t have any special meaning within the API. Should the API strip whitespace before creating the object?

Pro stripping

• Most of the time whitespace (at least leading and trailing) is unintentional
• It’s not visible anyway on a web interface (unless explicitly displayed as nbsp)

Contra stripping

• It’s wrong to modify user data
• An API is a programming interface, expect input to really be what the user wants

• user188153: I guess you can't get a useful answer without telling the full requirements. So: it depends.
• Bryan Oakley: Not enough information. It really depends on how important the whitespace is to the users. Some APIs might be ok to do this, some shouldn't do this.

Answer 1

Either the API should accept the whitespace as a legal part of the name, or it should reject it with an exception. Silently modifying input data is a bad idea in an API. Say the client wants to retrieve the object again by searching on the name. Or the client creates multiple objects, differing only in whitespace. Any number of things could go wrong in a way that will be surprising and possibly very hard to diagnose for the client.

It makes sense to sanitize end-user input to an UI, but this is an API, not an UI intended for end-users.