How to Build an SMS Service

SMS Interaction Design Considerations

Many of the same principles that apply to designing a software application apply to designing an SMS service: keep it simple, interface text should be meaningful and understandable to the user, always give the user a means to solve a problem that arises, etc. However, the unique qualities of SMS introduce some unique challenges and pitfalls, as well.

Short message length

The most obvious constraint on designing an SMS service is the maximum size of the message: in English, the best case, you get 160 characters to get your message across to your user. To put that into perspective, this sentence is 84 characters (including the period).

There are a several strategies you can consider as a service author:

• Aggressive editing: After you think you've pared down your message as short as it can go, take off another 10 characters. Try dropping nouns, verbs, and prepositions and see if the message still makes sense. Ask yourself if you need all the information and context you are providing in the message. Brevity is the soul of wit and the heart of SMS.

• Text speak:It may compromise the professional air of your service, but, if used properly, it could win you street cred. U can m8k yr msg shrtr! (Used inappropriately, this will win you ridicule.)

• Multiple messages: This should be your last resort, but you can send a single "message" as multiple SMSs. If you attempt to send a message longer than 160 characters, the carrier will typically break the message up into ...