Request Tracker (RT) is a ticketing system for IT, support and operations teams. It handles email sent to addresses such as support@, and offers custom lifecycles, a visual workflow builder and scrips that trigger actions when tickets change. It also provides reporting and dashboards, a knowledge base, asset management, SLAs, fine-grained access control, a customer portal and a REST 2 API. More than 35 interface languages and AD/SAML authentication are supported. RT is free software under the GNU General Public License, written in Perl, and developed by Best Practical Solutions LLC.
You can self-host RT on your own servers, which lets you decide where data resides and who can access it. Best Practical also offers Cloud RT, a managed environment in which the company handles servers, security fixes and disaster recovery. The pages consulted do not state which regions Cloud RT runs in, so ask if data location matters to you. Because the source code is open, there is no lock-in to the product itself, and you can keep operating it independently of the vendor.