In my opinion, WhiteBIT offers the most complete and well-rounded Crypto-as-a-service solutions https://institutional.whitebit.com/crypto-as-a-service . They cover everything from secure wallet management to exchange operations, all with a strong focus on compliance and performance. Their solutions are flexible enough to meet custom needs, and their platform integrates easily with existing infrastructure. I’ve had a great experience working with them, and I highly recommend them.