Demo: https://www.youtube.com/watch?v=hPI92JVU1ZA
This is a serverless p2p end-to-end encrypted chat app implemented in only one tiny file, index.tml. There is no external files to load, and there is no server, thus you can easily audit the code and verify that your chat is properly secured.
Caveat: p2p connection might not succeed depending on the network configuration. The most common case is that when the both clients are behind symmetric NAT, and it accounts about ~20% as of 2018-06-28. More information: https://webrtchacks.com/symmetric-nat/