Sub ID Central


Jessica Murray


T-Mobile has implemented a limit of 49 numbers per campaign in an effort to combat snowshoeing and ensure brands and campaigns are registered as intended (see note about ISVs below). If more than 49 TNs are legitimately required on one campaign, a Number Pool or Sub ID must be assigned to the campaign.

  • Sub IDs are Number Pool ranges that T-Mobile has preassigned to Bandwidth - the terms Number Pool and Sub ID can be used interchangeably, but the process of applying and assigning for each is different.
  • You must have campaigns registered in order for Bandwidth to assign a Sub ID to the campaign.
  • You can submit the request for Sub ID ahead of registration, but we can't functionally assign a sub ID without the campaigns.
  • You can also assign TNs to a campaign prior to Sub ID being approved but would need to reduce the TN quantity if the Sub ID request is not approved.
  • Number Pools and Sub IDs are for T-Mobile only; AT&T has a limit of 5,000 TNs per campaign.

The following use cases will typically be approved for a Sub ID at Bandwidth's discretion (the following use cases do not guarantee approval and registering your brands and campaigns in the appropriately is still required):

  • Group Messaging
  • Proxy (conversational) - typically this is where numbers are rotated through a number pool (does not apply when numbers are assigned to individuals)
  • Use cases that require locality (multiple offices/locations):
    • Franchises, banks, insurance agencies
    • Agents with dedicated phone numbers
    • Customer care
      • Hotels, hospitality, restaurants
      • Offices (Doctors, dentist, etc)
      • Contact centers
    • Churches
    • Emergency services (PSAP support)
    • Educational (multiple universities/schools)

If you have one of the use cases listed above or don't fall into any of the approved use cases but still have a legitimate need for >50 TNs per campaign, please fill out this form and a Bandmate will be in touch. Please note, sub ID responses can take up to two weeks but you can follow our Sub ID best practices (below) in order to have the most successful and quickest sub ID processing.

  • Checking the box for Number Pooling in TCR or Bandwidth's portal DOES NOT constitute a Sub ID approval. The application must still be submitted and approved by Bandwidth.

Note: ISVs are customers that support many brands (e.g., an ISV that supports 100s of dental offices). The requirement is that all of the individual brands the ISV supports need to be registered individually on their own campaign, as opposed to creating a Number Pool where these brands would hide behind the ISV avoiding registration.

Sub ID Best Practices

The following are guidelines that will help Bandwidth process your request in a timely fashion. Providing the level of detail outlined below will help give us a better picture of your traffic and therefore be able to make a determination on whether the use case should be approved for a Sub ID. We also advise providing this level of detail in the campaign descriptions and sample content as this is what the carriers will be reviewing if there is ever an issue with your campaign.

  • Use Case: This should mirror the campaign type from your campaign registration.  If the campaign is Mixed Use, please identify all appropriate use case categories.
    • 👎:  For a mixed-use case, only providing one of the use cases i.e., “Account Notifications” when the campaign also does “Customer Care”
    • 👍: “Mixed: Account Notification, 2FA, Customer Care, Marketing”
  • Description: Please be detailed when describing the types of messages that will be sent. 
    • 👎:  “Sending messages on behalf of Sales” 
    • 👍:  “Text messages sent by sales team members regarding pending deals and contract follow-ups” 
  • Sample messagesSample messages help Bandwidth and the carriers understand your use traffic profile and are particularly important for mixed-use cases. It is imperative that the sample messages in TCR highlight all types of messages being sent from the campaign.  The sample messages (as well as any actual messages sent out by you and your customers) should identify the message sender/organization. Note: We are not looking for an example of every single message you are sending, but a best practice is to include at least 1 sample per message type.  I.e., if the use case is Account Notifications and 2FA we need a  sample of the 2FA message and a sample of an Account Notification.
    • 👎: “Test”
    • 👍: “Good afternoon Mr./Ms. [insert name], we are contacting you to confirm your appointment with Highlander Dental Care on DD/MM/YYYY at HH:MM. Please reply “YES” to confirm or “NO” to reschedule.”
  • Reason for more than 50 numbers: We need a clear picture of why more than 49 numbers are needed for a single campaign.
    • 👎: “More than 50 Agents/locations” 
    •  👍: “We have 50 agents working on a personal basis with the customers, who expect that number to be associated with their agent.”
  • Explanation of how numbers are assigned:
    • 👎: "Each employee has their own phone line."
    • 👍: We have 25 locations in the US and each employee (~100 employees per location) has a dedicated line."
  • Documentation: Please attach screenshots of opt-in collection methods and any disclosures. 
    • The information collected on this form will be handled in accordance with Bandwidth’s Privacy Notice (
    • Note: In the event of a privacy concern, the Phone number and specific role assigned is an acceptable alternative to an individual's name.


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