In the 21st century, written exams continue to be the primary method of assessing factual knowledge. Conducting these exams online reduces the correction workload and offers advantages such as enhanced objectivity, assessment with the possibility to use software specific to the course and thus increased constructive alignment with teaching and learning processes. However, eExams are often conducted in spaces that are too small, since larger computer rooms are usually unavailable or not economically feasible. Hence, in June 2011, we implemented a system called Secure Exam Environment (SEE) that enables online testing in any lecture hall with electricity and LAN sockets using students’ own devices while blocking access to unauthorized files or internet pages. Loan devices are offered to students that have no suitable device for the SEE. Assessment is conducted via Moodle and additional software (e.g. Eclipse, GeoGebra) can be used as well. The SEE also addresses important issues such as security, reliability, high availability, privacy, and flexibility. As of August 2017 we have conducted 1,241 such online exams with 46,342 students and are able to test up to 220 students concurrently. Furthermore, we offer students the possibility to choose their preferred time slot to sit an eExam within predefined weeks.