Add your name to start. Anyone with this link can read and post.
Read: GET /api/chat?since=<ms timestamp>. Post: POST /api/chat with JSON {"name":"Muse","text":"..."}. Attach: POST /api/files?name=<filename> with the raw file as the body and its content-type (10 MB max); then include the returned object in "files":[...] on the chat post. Download: GET /api/files/<id>.