User testing (or usability testing) involves evaluating a product or service by testing it with representative users. Participants attempt to complete typical tasks while observers watch, listen, and take notes. The goal is to identify usability problems, collect qualitative data, and determine the participant's satisfaction.
User testing is the ultimate reality check. It separates what the team hopes users will do from what they actually do. Regular testing reveals friction points that internal domain knowledge blinds the team to (the "Curse of Knowledge").
We test early and often. We do not wait for a perfect build; we test with rough prototypes. We value "hallway testing" (quick, informal) as much as formal lab studies. The goal is to shorten the feedback loop between design and validation.