We have a proprietary rfid encoder with their software to make hotel room keys (BeLine Locks). It's bulky, and doesn't connect to PMS. Doesn't have any API. We learned how it works, and build our own little encoder software that provides API to make keys. Created a webapp that uses new API. Now, we can make keys from PMS. It may not save much time, but keys will be more accurate based on the reservation. And will be able to track who screwed up.

Another hotel uses different vendor locks with a different encoder. They don't also provide APIs or way to integrate. I just order a new encoder for that. Hopefully, we can figure that out too.