However, as a session replay industry competitor and a former security researcher for most industry players, I caution anyone thinking of using a side-project like this on production applications to proceed slowly with care.
Security and Privacy are extremely hard to get right here. The tricky thing about session replay analytics is that attackers have a huge attack vector, and compromise means gaining a treasure trove of all user data. The nature of replay is in a way a form of XSS. Modern security features help (like CSPs, iframe Sandbox attribute) but browser changes can cause issues.
Some of the challenges: - CSPs can often be bypassed using Google API libraries, <Object/>, <SVG> - Blacklisting <SCRIPT/> tags can often be bypassed with an XML namespace - CSS based data or password exfiltration. - Clickjacking, "data:" urls etc. - Could you imagine a web request proxy server deploying Service Workers? - postMsg() from further nested frames
Substantial work goes into sandboxing replay environments and limiting PII. Defense in depth is particularly important here. Enterprise level research, auditing, monitoring and care should be taken seriously.