SMS messaging in the US is governed by the CTIA. Strict rules are in place to regulate US messaging, which makes the right SMS implementation a deceptively challenging experience. This guide outlines the best practices to ensure your messaging is in compliance with regulatory and industry standards.
Unlike SMS in other countries, SMS features and regulations in the US and Canada are directly dependent on the source number used for sending an SMS. In the US, there are three possible types of source numbers that one might use to send an SMS:
To ensure high deliverability, it’s important to use the right source number type for your specific use case and daily volume. If you use the wrong source number, it may lead to excessive carrier filtering and poor delivery rates.
At Plivo, we support all the available source number types in the US. We work closely with our customers to help them choose the right product for their business.
Long codes are regular 10-digit phone numbers capable of sending and receiving texts and voice calls.
Long codes have the following advantages over other source number types:
Regular long codes are meant for person-to-person (P2P) communication, or conversational SMS. In Canada, they can be used for A2P messaging but they have low throughput per number. In the US, regular long codes don’t perform well for high-volume application-to-person (A2P) messaging use cases. For these, US mobile network operators have launched a service called 10DLC (10-digit long code) to explicitly allow A2P SMS traffic over long code phone numbers.
10DLC is the best phone number choice for most standard use cases, such as delivery notifications and two-factor authentication. They’re also best for businesses that want to have their messages come from familiar local numbers. By comparison, toll-free numbers have lower maximum throughput and take slightly longer to get approval for. And while short codes offer higher maximum throughput than 10DLC, they have higher monthly rental costs and one-time setup fees and take several weeks to provision.
A brand represents a business entity that is responsible for sending messages.
A campaign represents the type of messages the brand intends to send. The terms “campaign” and “use case” are often used interchangeably. Brands may run campaigns of several types.
Once you’ve registered your brands and campaigns you must link phone numbers to the campaigns. Once you’ve done that, messages sent from those numbers are considered 10DLC-registered and all the benefits of 10DLC apply.
Plivo’s customers can use the console or the SDKs to complete registration for themselves and their customers. Register your business as a Standard brand. Plivo strongly recommends taking advantage of optional vetting for your brand if your messaging volume exceeds 6,000 per day. Only vetted brands can take advantage of the highest possible throughput: 4,500 messages per minute.
Read more about how to get started with Plivo’s updated server SDKs for 10DLC.
We’ve all come across toll-free numbers — the 1-8xx customer care phone numbers we’re accustomed to calling when we want to speak to a business representative.
Toll-free numbers are well-suited for business messaging since people already perceive toll-free numbers as business lines. They can be used to send text messages at up to 40 SMS messages per second at a relatively low cost.
You can acquire SMS-enabled toll-free numbers on the Plivo console or by using Plivo APIs and start reaching out to your customers.
North American carriers have begun verifying toll-free numbers used for messaging. Verification is part of the Know Your Customer (KYC) initiatives undertaken to increase trust and reduce spam from A2P messaging. Verifying toll-free numbers serves the same purpose as registering long codes before they can be used as 10DLC numbers.
All messages sent toward Canadian destinations must be sent from verified numbers. Toll-free messaging volume toward US destinations that exceeds daily, weekly, or monthly limits must come from verified numbers.
|Unverified||- 500 messages per day
- 1,000 messages per week
- 2,000 messages per month
|Pending Verification||- 2,000 messages per day
- 6,000 messages per week
- 10,000 messages per month
All messages, regardless of whether they were successfully delivered, count toward daily/weekly/monthly limits. If, for example, a customer attempts to send 25,000 messages from an unverified (or pending verification) number on the first of the month, the first 500 (or 2,000) messages will be sent and the remaining messages will be blocked because of the daily limit. However, all 25,000 messages will count toward the weekly and monthly limits.
Any attempt to send more messages the following day will fail with error code 960 because of the weekly limit.
Note that the day resets at 12:00 midnight PST, while the week resets Sunday at 12:00 midnight PST. Month refers specifically to a calendar month.
To initiate a verification request for a single Plivo toll-free number, follow the process outlined in our support document.
Once you submit a request, Plivo passes it on to our carrier for review and moves the number to a “pending verification” status. Numbers that are pending verification don’t have daily or weekly limits but do have a monthly limit of 500,000 messages per month, to allow customers to increase volume gradually. Messages sent from a number that’s pending verification are still subject to carrier scrutiny and filtering, so Plivo recommends that you switch your production traffic to a particular number only after it has been verified.
When the carrier notifies us of the successful completion of the verification request, we change the status to “verified,” at which point it’s subject to the minimum amount of filtering. Verified numbers have no daily, weekly, or monthly limits.
If the verification request is rejected by the carrier, the number is again marked “unverified” and is again subject to daily, weekly, and monthly limits. We’ll send you an email that explains the reason for the rejection. Review the reason, consult with our support team, make changes, and resubmit your request.
Once verified, a number does not need to be re-verified for the same use case in the future. If you want to use the toll-free number for a different or an additional use case, you should submit a new verification request. Failure to do so can be considered noncompliance by the carriers and may result in your messaging services being suspended.
Have you ever noticed that the text messages you receive from your bank or from other large institutions generally come from four- to seven-digit numbers that don’t look anything like regular phone numbers?
These numbers are called short codes: special SMS only source numbers, typically provisioned by enterprises for their business-critical communications. This is because short codes offer the best possible reliability at the highest possible scale (100 SMS per second).
The good news is that we’ve made short codes an affordable option for small and medium-sized businesses. Check out our short code pricing list.
Short codes have the following advantages over other source number products:
The drawback is that the provisioning cycle for short codes is the longest out of all the available options — typically eight to twelve weeks. Why is that? Short codes and their corresponding use cases need to be preapproved by all network operators (Verizon, AT&T, T-Mobile, etc.) before you send one text out.
The good news is that once you’re preapproved, there will be no surprises once you actually go live.
|10-Digit Long Code||Toll-Free||Short Code|
|Regular phone numbers. Specific to locality.||1-8xx business phone numbers.||Four- to seven-digit specially provisioned and preapproved source numbers.|
|Best for business notifications and updates to customers.||Best for business notifications and updates to customers.||Best for business-critical notifications and updates to customers.|
|Buy using Plivo APIs or console. Requires completion of 10DLC registration, which can take up to a week.||Ready to use. Buy using Plivo APIs or console. Requires verification beyond certain sending limits, which can take 4–6 weeks.||Manual process. Provisioning short codes may take eight to 12 weeks.|
|Network delivery reports.||Handset delivery reports.||Handset delivery reports.|
|Relaxed spam filters, as use cases have been pre-vetted.||Sensitive spam filters tuned to block unwanted bulk marketing campaigns.||Relatively relaxed spam filters given that the use case and content must be preapproved to begin with.|
|Low rental cost per number. Additional cost for completing the registration process.||Relatively low rental cost for available throughput. No cost for completing the verification process.||Higher rental cost. Worth it for the high reliability at scale, as per-message cost is lowest.|