Know Before You Go
Every SMS message including the survey, alerts, workflows, and replies, all count as an SMS message and standard messaging rates apply.
Make sure to include something to identify you in your workflows, like your company name, in case your customer deleted their first SMS. They may not recognize the number when you send your workflow.
Verified and activated SMS customers will see two unique Actions available on the Workflows (lighting bolt) page.
External SMS Workflows
External Workflows are sent to Contacts. The set up is very similar to the Workflows you'd use for email.
For this example we'll be focusing on an NPS Detractor that hasn't left a comment, similar to the "Follow Up on Blank Comments" template available to you.
Remember: a Detractor is defined as an NPS score of 6 or less.
Unique to SMS Workflows is the "To" field and the "SMS Body" field
You'll notice with SMS, the message sends immediately and no delay is worked into the sending of this workflow.
How a Contact sees the Workflow
How it looks within AskNicely on the Reply Response Page 
Internal SMS Alerts
As mentioned in Know Before You Go, there is an individual cost to run these Workflows. You may want to use Emailed Custom Alerts for your team.
Mobile Number: This can be a static number where you'd include the internal mobile number that you'd want to have this alert sent to. It can also be a mobile number in a Custom Data Field tied to the Contact. You can use a Dynamic Field ie. {CSM_mobile_number} to automatically populate the number.
SMS Body: A single message limit is 160 characters, including spaces and characters that populate from the Dynamic Fields. AskNicely will send a maximum of 360 characters, or two messages.
FAQ
If I have both their email and SMS number and I have both detractor workflows for email and SMS, if I send an SMS survey, which workflow will they get?
They will receive a SMS workflow. If you send an SMS survey, they will only ever get SMS workflows. Our system is set up to block email workflows when the survey sending method is SMS.
Will the phone number the workflow comes from be the same the SMS survey came from?
Yes, it will send from the same number and show up in the same text thread.
Will I get an email alert when someone responses to an SMS workflow?
No. The response will show up on the Response Reply window like it would for email Workflows. However you will not get an email alert that someone has responded to your Workflow. We suggest to mark all Responses as "Open" when they come in and are updated, using the "Conversation Status" Workflow.
My region has the option for Alphanumeric Sending IDs. Does that change anything for Workflows?
Yes. Accounts that use Alphanumeric sending (a 5-digit short code only available in some countries) will not be able to receive any correspondence back from the Contact. Response data will still be accepted from the survey, but you will not be able to "close the loop".