I fully understand your need for qualified development for smart home. In this case, it is extremely important to pay attention not only to the technical skills of developers, but also to their experience in working with complex and large-scale projects. To do this, you should examine the company's portfolio, pay attention to customer testimonials and, of course, the technology they use. In the middle of this search, I came across an entertaining article on
https://www.cogniteq.com/internet-things that gave me insight into current trends and opportunities in the Internet of Things. I would recommend targeting companies that are not just following trends, but are actively applying innovation to their operations. Also, don't forget about the possibility of a long-term partnership: a reliable company will be able to offer you not only development, but also support for your product at all stages.