Multiple users posting to one database endpoint?

I'm new to web development and was curious about something. When posting to an endpoint to then receive a value from a server-side function, is it problematic if multiple users are writing to the same endpoint? Can this corrupt the value returned?

For instance, I'm using Stripe in a project and you're supposed to post to an endpoint to generate a user-specific ephemeral key. There's a 1-2 second delay in the response at times, so would there be a problem if two users posted to the same endpoint within a few milliseconds?