Hi @sagan, you will need to paginate the results using page and per_page query parameters.
For example, this is the HTTP request to get the second page with 50 records per page.
GET /api/v2/tickets?updated_since=2017-01-11T00:00:00Z&page=2&per_page=50 HTTP/1.1
Host: medzed.freshdesk.com
You will get a link HTTP response header which will have the address for the next page if a next page exists in the list of records.