How to Retrieve Last Login Dates for Multiple Users in FusionAuth via the Search API

wesley

We have ~8,000 usernames/emails and want to look up each user’s last login date. The UI seems to allow searching only one email at a time. Is there a way to upload a CSV of usernames and get all of their lastLoginInstant values?

wesley

FusionAuth doesn’t support uploading a CSV to retrieve last-login timestamps. However, you can do this efficiently with the Search for Users API and return lastLoginInstant for many users at once.

How to do it (batch via API)

Use the User Search endpoint
POST /api/user/search (set your X-FusionAuth-TenantId and Authorization headers).
Send an Elasticsearch query using terms to match a batch of emails/usernames, and read lastLoginInstant from each returned user:

 {
  "search": {
    "query": "{\"terms\":{\"email\":[\"a@example.com\",\"b@example.com\",\"c@example.com\"]}}",
    "numberOfResults": 500,
    "startRow": 0
  }
}

Swap email for username if that’s what you have.
If your list is large, chunk it (e.g., 200–500 logins per request) and paginate with startRow / numberOfResults.

(Optional) Filter by last-login date with a range query on lastLoginInstant:

 {
  "search": {
    "query": "{\"range\":{\"lastLoginInstant\":{\"gte\":\"2025-10-01T00:00:00Z\"}}}"
  }
}

You can also query by epoch millis if you prefer.

Map results
Each user object includes lastLoginInstant (epoch millis). Convert to your desired timezone/format in your script and write out a CSV.

Tips

If you need all users in a tenant (not just your list), you can search with a wildcard or a match-all query and page through results, then filter locally.
For ongoing metrics, consider subscribing to user.login.success webhooks and recording last logins as they happen.

Docs:

Search for Users API (Elasticsearch): https://fusionauth.io/docs/apis/users#elasticsearch-search-engine