Scribbr’s Plagiarism Checker is powered by elements of Turnitin’s Similarity Checker, namely the plagiarism detection software and the Internet Archive and Premium Scholarly Publications content databases.
The add-on AI detector is also powered by Turnitin software and includes the Turnitin AI Writing Report.
Note that Scribbr’s free AI Detector is not powered by Turnitin, but instead by Scribbr’s proprietary software.