If you’re using the standard join_url (https://zoom.us/j/meetingId…), this should default to the app, if it is installed.
However, if you wish to open in the web client instead, you can alter the join_url to include /wc instead of /j.
More simply put, you can use our Web Client as the join_url without leaving the website by replacing /j/ with /wc/ :
https://zoom.us/wc/{meetingID}/join .
Let me know if this is what you’re looking for!
Thanks,
Will