First time I tried to login to Netflix at a hotel TV I almost gave up. The remote was having only four arrow keys and a number pad. My password was 18 characters with symbols. Whoever designed the login screen had either never used it themselves, or they had decided suEering builds character. After few years, the same TV’s started doing something different. They showed us a short code and an URL. I opened phone, typed the URL, entered the code and we are in. No remote-control circus. No password on a TV. That is OAuth 2.0 device authorization grant. Most of the people just call it that device flow. If we run aws sso login, gh auth login, or signed into Spotify on an Xbox, we have already used it. And if you are build a backend for a CLI, an IOT device, a smart TV app or anything where typing a password is really painful or not safe, we should end up implementing it sooner or later. Here is the step by step Step1: Assume we are building a CLI called mycli.…