I am designing an account creation form that will prompt for username and pass phrase. The username will represent the user for login and communication with other users. It will also be used across multiple protocols (e.g. email prefix), including ones not yet planned for, so I need to severely restrict input to values that will be compatible with multiple protocols (e.g. no periods). The restrictions are as follows:

  • must begin a-z
  • can be followed by a sequence of characters from a-z and/or 0-9
  • must be lowercase
  • nothing else is permitted (uppercase, punctuation, unicode...)

So a number of typical workarounds for usernames are not permitted: jane.doe, JohnDoe and Björk_Guðmundsdóttir would all be invalid.

What could I call this field so that it still feels like the user's identity, without disappointing them (too much) when they realise the restrictions?

(I thought of having a separate "full name" or "what shall we call you" field but I can't guarantee that I'll use that functionality.)

  • Your design would really piss me off as a user. And if you want to send me emails, ask me for me email address and accept if I tell you you can't have it.
    – gnasher729
    Jun 23, 2017 at 22:29

1 Answer 1


I see no reason why you shouldn't call it Username. Because that's what it is, and that's what the users will expect to see.

However, it's important that you make the user aware of the limitations. Helper text in the style of the Material Design guidelines is proven to work well.

Material Design Helper Text for constrained username

An of course, validate the users input and let them know if they've entered something wrong after they've de-selected the username field.

Detailed information on validation can be found in this Designmodo article.

  • 2
    This makes the most sense. Concern about how users will feel about the restrictions could be catered for by providing an icon or text link (near the restriction information) that invokes a tooltip. "Why all the restrictions?" "Your username will be used for multiple purposes e.g. email prefix, ....., ......., and needs to be as compatible as possible."
    – dennislees
    Jun 22, 2017 at 16:58
  • thanks also for the screenshot, this expression of the restrictions is really clear and unambiguous
    – lofidevops
    Jun 23, 2017 at 11:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.