Hello there! 
Achievements are account-wide, but there is no endpoint to directly get them. So we need to request the Account Profile Summary endpoint, get the first character above level 20 (or is not exposed) and request its Character Achievements endpoint.
Would be great to have an Account Achievements endpoint (like Account Collections ones). 
Have a great day!
–Zalki
unlikely to get an account level one as almost all these calls require the user to auth the calls, just pull one character from the account and your good
Thanks for your answer.
I understand that. What I want is to get accomplished achievements, but I need two API calls:
The Account Profile endpoint returns all characters, even those under level 20. 
I have the access token (Authorization Code Flow), so it would be great to have an Account Achievements endpoint to get them. For example:
/profile/user/wow/achievements
BECAUSE they are account wide ALL characters on the account return the same achievement endpoint data
and your access token is for the api client Account endpoints require a User token to pull not the same
So, it looks like Ulminia still doesn’t understand. The API does not return the status as TRUE for all characters once an achievement is completed by a single character on the account. BUT what I did see is… it appears to populate the completed_timestamp when another character has indeed completed it.
So you could just go based on that alone or do some extra logic of when status = FALSE check the completed_timestamp to see if it was done.
ok i see the issue yes the timestamp is set when wb complete but criteria => is_completed is false there use to be a is account complete field but its been removed, but i would say their wont be any updates on this as much as we would like it i cannot see it happening, all my code does is looks for a completed_timestamp if its set then its complete