Spread is Reasonable's email marketing platform, and I was tasked with adding support for sending SMS. The SMS Gateway allows for clients to send both promotional SMS (ie, marketing campaigns) and transactional SMS (ie, a verification code) using China Mobile as the service provider.

I was responsible for developing the webpage GUI (for clients to craft their SMS), as well as the backend SMS Gateway itself.

The SMS Gateway was developed with Web API in ASP.NET (VB). Basic features I developed include SMS throttling (to prevent sending too many SMS requests/second to China Mobile), Hong Kong Do-Not-Call list support (as well as making sure the Do-Not-Call list is up to date) in order to prevent government fines, as well as authenticating the API caller.

Another application I helped develop alongside the SMS Gateway was the "SMS Service" (developed in VB), an always-available Windows Service that calls various APIs (including our SMS Gateway) to send the SMS. It supports sending SMS to Hong Kong, Macau, Taiwan, Mainland China, and various other international markets.