Every AI product now needs a chat surface, and the chat surface is where users decide whether the product feels finished. Smooth token streaming, sources you can actually check, code that opens somewhere better than the middle of a transcript, a stop button that works mid-answer - none of it is hard on its own, but getting all of it to feel right takes weeks. That's why "AI chat UI kit" has become its own category. The options split into two very different kinds of thing, though, and picking the wrong kind costs more time than it saves. This is an honest comparison of six worth your time.

Templates vs. component libraries

Before the list, the split that matters most. A chat template is a whole working app you fork: routes, layout, thread sidebar, settings, a design. A component library gives you the pieces - a message list, a prompt input, a markdown renderer - and you assemble the app yourself. Neither is better.…