Can we have the same external_user_id for all users logging into embedded content?

[mandy_chan]

Technically, the answer is yes. However, there are potential issues to consider:

1. As noted in docs, this value must be unique for a given set of permissions, user attributes, and models. So, for example, if the different users will have different permissions, they’ll need two different external user IDs rather than sharing the same external_user_id. Failure to meet this requirement will cause data leakage 
2. Be aware of the per user query limit is 15 by default, which means all the users viewing the embedded content will share this 15 concurrent query limit. When one user is loading dashboard A with 20 queries, the other user who tries to load another dashboard will be delayed until the number of concurrent queries of this embed user account is less than 15 again. If they use different external user id, then each of them will be allowed to run 15 concurrent queries.
3. There may be contract compliance issues with using the same external_user_id for multiple users on your application, so you'll want to check with the customer success team to see if this kind of setup is okay.

So for the best performance, user experience, security, and contract compliance, it will be better to have each embedded user have a unique external_user_id.