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Messaging FAQs

What are the essential steps I need to take to start sending messages?

  1. Create a Brand.
  2. Register a Campaign.
  3. Assign phone numbers to the campaign.

Full details are explained on our Messaging Campaigns Help Page.

What is 10DLC?

10DLC is a type of phone number. Short for 10 Digit Local Code, it is a type of phone number that includes an area code followed by 7 additional digits indicating a specific channel. For example, +12345678910, where the "+1" indicates the country, the "234" indicates the area code, and the remaining digits indicate the channel.

What is the difference between 10DLC and Toll-free phone numbers?

Toll-free numbers, although slightly more expensive, allow for increased throughput out-of-the-box. They also have a registration process tied to them, however once complete, have a higher deliverability rating than traditional 10DLC numbers.

What is The Campaign Registry?

The Campaign Registry is a platform that was created in partnership with a company called Kaleyra and several Mobile Network Operators (MNOs). The platform itself acts as a source of information about every 10DLC number being used for outbound SMS through A2P routes in an effort to discourage spam in the industry. In short, any and all 10DLC numbers that are to be used for SMS in SignalWire's platform must be registered through the Campaign Registry. You can find more information about the Campaign Registry in-depth here.

Can we programmatically create campaigns and brands?

Yes! You can do this through the SignalWire REST APIs. Check out the documentation.

How many messages can I send out?

The number of messages you can send out depends on a few different factors. If you are using a toll-free number, there is no real limit outside of throughput in regards to the amount of messages you could feasibly send. With 10DLC, it depends on your registered use case with the Campaign Registry. AT&T provides limits a limit on the amount of texts per minute you can send to an end-user at the campaign level whereas T-Mobile limits the overall amount of SMS per day you can send to and end user at the brand level. For more information around this, feel free to read Campaign Registry - All you need to know.

What content is not allowed?

There is some content that is explicitly disallowed from being sent via SMS/MMS with SignalWire. You can see this list in full detail here.

What are NAFs?

Network Access Fees (NAFs) are additional fees that are charged by Mobile Network Operators (MNOs) charge on a per-SMS/MMS basis for the ability of that SMS/MMS to be passed-through their network.

Are all the NAFs the same?

No. Every MNO has their own NAFs set by them for inbound and outbound SMS. To see a list of NAFs broken down by MNO and direction, you can look here.

How do I get higher throughput?

For verified toll-free numbers, you can contact sales at to increase the throughput of those numbers up to 100 MPS for an additional price.

Can I just send SMS/MMS to a specific carrier like Verizon?

SignalWire does not provide a way to explicitly send to Verizon end-users or end-users of any other MNO.

Do I register toll-free SMS/MMS traffic?

You can verify toll-free traffic by opening a support ticket with us. Our team will follow up with the forms and information we need from you within that support ticket.

Does SignalWire manage opt-outs?

No. Customers are responsible for handling inbound stop requests and removing those customers from subscriber lists. Messages should not go out to these numbers again unless they have opted back in via an Unstop request.

What is considered a high opt-out rate?

Carriers consider anything more than 5% opt-out to be a high rate for consumers who have opted in and therefore should want to receive these messages.

Can I turn off inbound SMS?

Not currently. We have no way to turn off inbound SMS at this time. You can leave your numbers unset up for messaging and nothing will happen when inbound messages come into the numbers though!

Do you have a messaging queue?

We do not have a "scheduled" queue, but messages that exceed your throughput will be entered into your space's backlog and sent when possible. Read about the backlog and queue system here! The default message backlog is 10,000 for the entire Space. These limits can be increased based on the use case and individual approval following an account verification request.

Am I billed once a message is in the queue?

Messages are charged when they are 'Sent' successfully - meaning they leave our network without issue. They are charged regardless of whether or not they deliver after they have left our network. You are not charged while your messages are queued or 'failed' (failed meaning they never left our network).

Where can I find information on specific error codes?

Visit our error code explanation page for details. Also, to find out what you can do about error codes, take a look at How to Troubleshoot Common Messaging Issues.

Need the Campaign Registry FAQ?

These FAQs address general messaging topics. For FAQs on Campaign Registry details, visit the Campaign Registry FAQs