Why does the number for a response option change when responding via SMS?


When I get a text message on my phone, it says something like  "Reply 3 to Accept, 4 to Escalate, 5 to Close". But the next time I get a notification for the same type of thing (meaning the same workflow and form), the numbers might be "Reply 7 to Accept, 8 to Escalate", etc.  Why isn't the first option always "Reply 1", the second "Reply 2", and so on, like it is when I get notified over the phone? 



  • All versions of xMatters
  • SMS notifications (all carriers)


The short answer is because SMS stinks and isn't the best choice for important communications! The real answer has to do with the way SMS works and the way xMatters tracks notifications.

How SMS works

SMS messages are "stateless" - meaning they don't carry any extra information about any other part of a conversation. When you reply to an SMS notification, there's nothing in the message you're sending back to xMatters that links it to the message you're responding to.

"But when I look at SMS messages in my phone, I can see conversations!" True, but they're only grouped together by phone number, and sorted by the time they were sent. That's all your texting app has to work with. (Except in the case of group messages, when it also has the luxury of knowing who else the message was sent to.)

So, when you respond, the only information available is a phone number and the message content. xMatters can't even rely on the time when the message came in, because you might have responded to a newer notification first, before responding to an older one.

How xMatters tracks notifications

To get around this limitation, every time xMatters prepares an SMS notification for you, it figures out what the lowest available numbers are that it can assign to the first response option and then increments that number for each additional choice. The lowest number available depends on how many notifications you've received for this event, how many active notifications are currently targeting you, and a few other factors.

When an SMS response message comes in, xMatters uses the phone number to identify who is responding (i.e., you), and the message content (i.e., the number) to identify what your response is supposed to be and the event you're responding to. 

On a side note...

xMatters uses numbers as response choices to make sure your SMS responses are as short and easy to submit as possible (and so you don't have to type the response choice exactly, which can trip up so many people, especially when responding in a hurry using only their thumbs).

You also might be wondering what the numbers you specify for response options on the Responses tab in a workflow are used for, since they don't apply to SMS notifications. These numbers apply only to phone interactions:


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  • I am glad I came across this. I was wondering why the response options kept increasing.