In the API how do I do a where for user id

To filter profiles by a specific user ID using the Engage API, you use the where parameter with a segmentation expression, or you can use the distinct_id or distinct_ids parameters directly.

Pass the user's distinct ID directly:

POST https://mixpanel.com/api/query/engage?project_id=YOUR_PROJECT_ID
Content-Type: application/x-www-form-urlencoded

distinct_id=YOUR_USER_ID

You can filter using a segmentation expression with the where parameter:

where=properties["$distinct_id"] == "YOUR_USER_ID"

curl --request POST \
     --url 'https://mixpanel.com/api/query/engage?project_id=YOUR_PROJECT_ID' \
     --header 'accept: application/json' \
     --header 'authorization: Basic YOUR_TOKEN' \
     --header 'content-type: application/x-www-form-urlencoded' \
     --data 'distinct_id=YOUR_USER_ID'

[Engage API docs]

Note: For projects using the Simplified ID Merge API, the canonical distinct_id is always set to the $user_id after identification. [Identifying Users] So make sure you're querying by the canonical distinct_id (i.e., the $user_id value you passed to identify()).

why do I just get 31 results. in mixpanl there are hundreds kapa.ai

The Engage API returns results in pages, with a default page_size of 1000 records per request. If you're only getting 31 results, it's likely not a pagination issue — but rather that your query is only matching 31 profiles.

However, if you believe there should be hundreds of results, the most common cause is that the API returns paginated results and you need to iterate through pages to get all of them. Here's how pagination works: [Query Profiles]

// Get the first page of data
this_page = query_api(where=YOUR_SELECTOR_EXPRESSION)
do_something_with_response(this_page)

// Keep querying if results equal page_size
while (length of this_page.results) >= this_page.page_size:
    next_page_number = this_page.page + 1
    this_page = query_api(
        where=YOUR_SELECTOR_EXPRESSION,
        session_id=this_page.session_id,
        page=next_page_number
    )
    do_something_with_response(this_page)

Key points:

Also note that the Engage API has a rate limit of 60 queries per hour and a maximum of 5 concurrent queries, so be mindful of that when paginating through large datasets. [Query Profiles]

If pagination isn't the issue, double-check your where filter or distinct_id parameter — it may be narrowing results more than intended.