Experience. The more projects your IoT app development company of choice has, the better. If they worked with products that are similar to your business idea, there’s a better chance of them delivering good results
Reputation. Check out the reviews of a development company. If there are many satisfied clients praising specific things in the work process — what went right — it’s probably a trustworthy vendor. Also, video reviews can lend more credibility — they take more effort to make, so it’s usually tedious to fake them
Transparency. Trustworthy IoT companies won’t keep their prices and the development process secret. If there are any unexpected changes, they’ll tell you straight away. It’s in their interest to develop a good product, same as you. It’s a red flag if they evade answers when it comes to deadlines and pricing