Honestly I wish we could just abolish first and last name fields and replace them with a single free text name field since there's so many edge cases where first and last is an oversimplification that leads to errors. Unfortunately we have to interact with external systems that themselves insist on first and last name fields, and pushing it to the user to decide which is part of what name is wrong less often than string.split, so we're forced to become part of the problem.

I did this in the product where I work. We operate globally so having separate first and last name fields was making less sense. So I merged them into a singular full name field.

The first and only people to complain about that change were our product marketing team, because now they couldn’t “personalize” emails like `Hi <firstname>,`. I had the hardest time convincing them that while the concept of first and last names are common in the west, it is not a universal concept.

So as a compromise, we added a “Preferred Name” field where users can enter their first name or whatever name they prefer to be called. Still better than separate first and last name fields.

One field?

Like people have only one name... I like the Human Name from the FHIR standard: https://hl7.org/fhir/datatypes.html#HumanName

People can have many names (depending on usage and of "when", think about marriage) and even if each of those human names can handle multiple parts the "text" field is what you should use to represent the name in UIs.

I encourage people to go check the examples the standards gives, especially the Japanese and Scandinavian ones.

It’s not just external systems. In many (most?) places, when sorting by name, you use the family names first, then the given names. So you can’t correctly sort by name unless you split the fields. Having a single field, in this case, is “an oversimplification that leads to errors”.