A lockdown browser is a stripped-down, dedicated browser application designed specifically for assessment delivery, configured to prevent common forms of online cheating by restricting what the candidate can do on their device during the exam. Typical restrictions include disabling copy-paste, blocking new tabs or windows, preventing access to other applications, disabling screen capture, and in some implementations restricting external device connections. Lockdown browsers are the most widely deployed anti-cheating technical control in online assessments and are supported natively by LMS platforms and proctoring vendors such as Respondus and Proctorio. However, they are not foolproof: a candidate with a second device — a phone, tablet, or separate computer — can access forbidden resources without the lockdown browser detecting it. They also introduce friction for learners using assistive technology such as screen readers, since many accessibility integrations depend on browser features the lockdown application disables. Compatibility testing across operating systems and accessibility tooling is therefore mandatory before deploying a lockdown browser in a production exam. Lockdown browsers are most effective as a deterrent that raises the effort required to cheat rather than as an absolute barrier, and they work best in combination with an assessment design that makes simple look-up answers less useful.
