SMS Carrier Violations


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If you notice some of your messages are being marked as "Undelivered", there's a possibility you may have received a carrier violation. If you encounter a carrier violation, you should consider adding more numbers and enabling Smart Routing. As a general rule of thumb, we strongly recommend that you have at minimum 1 number per Location, plus one number per 30,000 message segments sent per month.

What's Covered

What causes a Violation?

There is active efforts from phone carriers to seek out spams and might flag your messages causing the message to be undelivered. Carriers do not advertise how their spam filters work to avoid reverse engineering. Every carrier has their own stipulations, and there are also a number of other factors that could contribute to receiving a carrier violation. However here are some general ones:

  • Your applicants complained to their carrier that they were receiving unwanted messages.
  • Carriers are filtering your messages because the volume of messages you are sending from each standard number is too large.
  • You are sending similar or identical content from a long code to many multiple numbers within a short period of time.
  • You have multiple Openings in each Location that are sending messages in quick succession from the same number to different numbers.

Scenarios at risk of a carrier violation

If you have 15 Openings in one Location and they're all using the same phone number to send messages there is a chance that your number could be flagged as spam by the carriers resulting in undelivered messages. Conversely, if you have 1 Opening in a Location, but you send out 400 messages to 200 unique recipients in a day in that Location, you also run into the risk of the carrier flagging your messages as spam.

The general rule of thumb is no more than 200 unique recipients per day from a long code at a rate of no more than 15-60 messages per minute to avoid possible carrier end filtering.

Smart Routing

Smart Routing can help lower the chance of carrier violation by automatically rotate through all of your numbers you own to avoid a single number from being used excessively and causing the carrier to flag these messages as spam. Smart Routing chooses the best number based on what country the recipient is in and how many SMS messages that number has sent. That number is then assigned to the applicant and sticks with them throughout the process (unless it is deleted). There is no additional charge to enable this feature.


Amount of numbers you need with Smart Routing enabled

As mentioned, we suggest that you have at least one number per Location, plus 1 number for every 30,000 message segments you send per month, and a few buffer numbers. If you have 40 locations and send 60,000 message segments per month, you should have 40 numbers + 10 numbers, for a total of 50 numbers.

Buffer numbers are recommended, as your actual rate of sending SMS may ebb and flow based on applicant numbers and communication with your applicants can be affected.

Pricing for additional numbers can be found on the Pricing tab of your SMS page in Company Settings.

Short Codes

For higher volumes of messaging Fountain offers short codes phone numbers. Please reach out to your Customer Success Manager if you are interested in purchasing a short code for your messaging usage.


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