# What makes a valid username on JupyterHub / TLJH?

**URL:** <https://discourse.jupyter.org/t/what-makes-a-valid-username-on-jupyterhub-tljh/18592>\
**Category:** The Littlest JupyterHub\
**Created:** [March 23, 2023, 8:43am UTC](https://discourse.jupyter.org/t/what-makes-a-valid-username-on-jupyterhub-tljh/18592 "2023-03-23T08:43:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fmaussion](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/fmaussion/32/390_2.png) [@fmaussion](https://discourse.jupyter.org/u/fmaussion)\
**Post date:** [March 23, 2023, 8:43am UTC](https://discourse.jupyter.org/t/what-makes-a-valid-username-on-jupyterhub-tljh/18592/1 "2023-03-23T08:43:47Z")

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Hi! As a hub admin I wondered what consists a valid username for hub users. Are there any pitfalls with special characters, etc? Is it a good idea to use someones email address for example?

I could not find any info on this [here](https://tljh.jupyter.org/en/latest/howto/auth/firstuse.html)

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**Author:** ![manics](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/manics/32/85_2.png) [@manics](https://discourse.jupyter.org/u/manics)\
**Post date:** [March 24, 2023, 7:29pm UTC](https://discourse.jupyter.org/t/what-makes-a-valid-username-on-jupyterhub-tljh/18592/2 "2023-03-24T19:29:53Z")

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On TLJH all users are created as operating system users, so that’s probably the main restriction on supported usernames. I can’t think of any other limitations at the moment.