Justin Halsall builds tools that let developers see exactly how users interact with their software. He maintains the open-source session replay library rrweb and co-founded Kilo Code.
He focuses on bridging the gap between code deployment and user reality, especially in making session data usable for AI agents. On stage, Justin dissects the psychology of live coding competitions and hosts satirical tech news panels that test audiences on bizarre industry headlines.
Outside of his startup work, he contributes to the Apache Software Foundation.
