I'm not sure I can attract some big companies. Yes, your most likely target customer in my opinion would be a service provider for lots of small to mid-size co

I'm not sure I can attract some big companies. Yes, your most likely target customer in my opinion would be a service provider for lots of small to mid-size companies (aka me). Individuals will just use SMS. Larger companies will implement this on their own. My best advice is to make your service as logistically simple as possible. In other words: - Forget device ID. Almost every mobile communication device already has an ID, it's called a phone number --- which your customers will most likely already have stored for other reasons. Any mobile device that an individual regularly carries is likely to have one. - Forget device type. Most people don't care what "type" of device it is. Do you store this info in your contacts list? I don't and most companies don't either. If you need this, collect it from your mobile app and store it. Most customers won't be burdened with doing your logistics for you. - Grouping is essential for convenience but also efficency for yourself and for customers. Lots (if not most) business notifications need to go to more than 1 individual. Doing this one person at a time is unnecessarily tedious and time consuming. An acceptable alternative would be to simply allow the "send message" API call to accept multiple recipients. - Do allow customers to identify themselves with a user friendly name that individuals can select or input to receive notifications from. - In my opinion, your market opportunity here is to build a send only version of SMS that is just as easy to use while costing less. But you have more work to do.