Hello there. I am web developer. Short time ago I was working on project which required integrations with a lot of exchanges and coins / tokens api's.
Here list of exchanges I integrated myself: binance, cexio, bitso, bitrex, liqui. The common issue for most of exchanges is key expiration period. Yes, sometimes its problematic to track expiration date.
Since project under NDA I cannot share with u details. Hope u understand me and awating your response.