How to add access an external user to only one project

[M C Fuentes]

Hello,

I need your help to add a user, which a client, to only one project, I have been traying following the instruction given in other answers but it didn't work the main issue was that the client can see all the project.

Thank you in advance

Regards,

[Isaac Montes]

May I ask are you using JIRA server or Cloud

1. Add new group for external users
2. Add user to the particular special group 
3. Add group to have JIRA application login, meaning they can login.
4. now the user should be able to login but not see any JIRA projects or data unless you have project permission set to anyone 
5. add the user or the group to the proper project role (or permission)
   1. This will have at least the view issues permissions.

If you want to be more granular add issue security to the project 

https://confluence.atlassian.com/jiracoreserver073/adding-users-to-your-project-861255666.html

https://confluence.atlassian.com/adminjiraserver073/configuring-issue-level-security-861253265.html

[Hari Shankar]

Quick question, does this apply for guest users? Meaning if I want to provide a temporary access to a guest to just see an issue/ticket, is that still doable without a separate license for the guest user?