At the Previous Company I was in (Bindo Labs) I was coding the NFC Payment Integration with the Point of Sales System (POS). One of the requirements for the integration was that every transaction has to happen less than 0.5 seconds including the hardware card-reading part. So I ended up having to wave the card around the reader all day testing it. I thought of building a automated testing robot but tight deadline prevented me from diverging, and it didn't end up happening.

I'd be curious to know how big a business it is for you now that it's 5 years past. Sounds like a very interesting case-study.