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A2P 10DLC in Conversations

In this guide, you will find answers to common questions about A2P 10DLC and how it relates to Twilio Conversations.

For more general information and onboarding guides, please see:

What is A2P 10DLC? What’s happening?

As stated in our the A2P onboarding documentation:

U.S. Application-to-Person 10-digit long code (A2P 10DLC) messaging is the latest offering from U.S. carriers to help support the growing ecosystem of businesses texting their customers while protecting end users from unwanted messages. 10-digit long codes have traditionally been designed for Person-to-Person (P2P) traffic only, causing businesses to be constrained by limited throughput and heightened filtering. The launch and support of A2P 10DLC across all carriers in the United States provides good actors with increased deliverability and throughput, but also requires additional registration to build trust with carriers. There are associated fees with this registration process and also per-message carrier fees.

A2P use cases, including Twilio Conversations API use cases, run afoul of the standard P2P regulation to various degrees. The incumbent P2P regulatory guidelines were opaque and loosely-enforced, which led to traffic being filtered or throughput-constrained arbitrarily.

In broad strokes, the A2P 10DLC transition ends the grey area of P2P-style regulation. The carriers aspire to formalize content regulation rules, to make explicit throughput allowances, and to reduce filtering rates in exchange for pre-registration and compliance by customers.

Frequently Asked Questions for Conversations and A2P 10DLC

Is Conversations traffic subject to A2P governance?

Yes! Per the public support documentation, any SMS traffic through Twilio is governed by A2P. The carriers’ position is that any traffic that moves through a computer program is A2P traffic, even if the use-case is legitimately peer-to-peer.

I think I’m a "small" use-case that doesn’t need to register. Would carriers agree?

The A2P compliance landscape is still changing. For more information on the fee and registration schedule, please see Dates and deadlines for business registration in our Support article covering A2P 10DLC.

At this time, hobbyist developers sending out very low-volume messages do not need to register. As stated in our Support article, Twilio will share new information via email and updated articles should thresholds and/or requirements change.

All businesses benefit from lower filtering rates once they register with A2P 10DLC, assuming their traffic is compliant. Furthermore, some carriers (so far AT&T) will increase their messaging fees for unregistered traffic on May 1st, 2021. (See our Support article What pricing and fees are associated with the A2P 10DLC service?) Registration is always an option, also for small businesses.

How will I know if carriers think I’m in violation? Will my traffic just be shut off or is there a system of warnings/escalations?

The answer here depends on your assigned Trust Score:

When you complete the registration of your Brand and Campaign(s) for A2P Messaging through the Twilio Console, that information is sent from Twilio to The Campaign Registry (TCR), a 3rd party at the center of this new registration system. TCR uses a reputation algorithm to review specific criteria relating to your company, and assign a “Trust Score” that will determine your messaging throughput.

Details on the reputation algorithm and the specific consequences aren’t yet clear. However, the position of the carriers is that customers with a high trust score will receive favorable (monitor-only) treatment. Customers with lower trust scores will see more proactive filtering on the part of the carriers.

What kind of Campaign should I select?

This depends entirely on your business; there is a long list of campaign types among which you can select when applying for an A2P campaign.

At present, the A2P environment incentivizes single-purpose channel use. Accordingly, “Mixed” campaigns are likely to receive the highest fee structure and the lowest allowed throughput. If you can identify with a more specific campaign type, we recommend it.

How do I map my Conversations to Campaigns?

All A2P Setup is taken care of by assigning your numbers to a Sender Pool in a Twilio Messaging Service. The A2P Onboarding Documentation describes this process in detail (including specific guidance for ISVs). This assignment registers the number in The Campaign Registry, after which all Twilio traffic from that number is applied to the campaign. When using the Conversations API, you don’t need to do anything differently.

Note: Each of your Conversations is assigned a Messaging Service SID on creation. This has no effect on your A2P Campaign assignment. For each outbound message, the A2P campaign is selected entirely based on your Twilio Number’s Sender Pool membership.

Loading Code Sample...
        Take note of the "Messaging Service SID" property

        See the Messaging Service SID associated with a Conversation

        Take note of the "Messaging Service SID" property

        Should I use just one Messaging Service for all my Conversations?

        For small use-cases under a single brand, yes. A single Messaging Service is the simplest way to organize your Twilio account, and requires zero extra code to benefit. If your business is a small one — fewer than 400 numbers with less than 50 messages/second overall — and your business messages under its own brand (providing service to your own customers), we suggest:

        1. Configure a single campaign with the most appropriate use-case from the above list.
        2. Configure one Messaging Service with that campaign.
        3. Assign all of your phone numbers to this messaging service (NB: the terms of your registered A2P campaign must apply equally to these numbers)

        Having done this, all of your numbers will be registered with one campaign, ergo they will inherit the same trust score and throughput consideration by carriers.

        Optionally, you may want to configure that messaging service as your Default Messaging Service, so you can configure Autocreation for your application.

        What if I’m an ISV?

        An ISV is a customer using Twilio to provide Messaging Services to other businesses, each of which has their own brands. ISVs must register A2P campaigns individually for each brand to whom they provide Messaging Services. Accordingly, you’ll need to use unique Messaging Services for each of them: the "one Messaging Service" pattern cannot apply.

        The good news is that multiple Messaging Services doesn’t require re-architecture of your Conversations API-based application: any number of Messaging Services can participate in the same Conversations Service without restriction, and without any impact to the applicability of Twilio Phone Numbers to those Conversations. Throughput and Trust Scores are assigned per phone number.

        Please see our ISV US A2P 10DLC Onboarding Guide.

        What if I have a large business?

        If you have thousands of phone numbers using Conversations (This is especially common for personal-shopping, real-estate, and wealth management use-cases.), you’ll confront a couple of limitations when working through a single A2P Campaign:

        • Limited Messaging Throughput: If you direct all of your messages through a single Messaging Service (ergo a single A2P Campaign), your entire application will be limited by the assigned throughput for that campaign.
        • Sender Pool Size Limits: Each Messaging Service can have at most 400 phone numbers. This is a soft limit, and we can help you raise that within an order of magnitude (contact Support). However, the larger the pool, the larger the problem of throughput mentioned above.

        Accordingly, if you have thousands of numbers you should be using multiple Messaging Services and accordingly multiple campaigns. Your phone numbers, assuming they apply equally to the campaigns you register, should be evenly distributed among those Messaging Services to spread out the throughput required over time.

        These Messaging Services can (but don’t necessarily need to) all point to the same Conversations Service for purposes of autocreation. There is no limitation on how Twilio Phone Numbers can be combined with each other within Conversations, including for group texting.

        How do I migrate existing Conversations to A2P?

        All A2P Setup is taken care of by assigning your phone numbers to a Sender Pool in a Messaging Service. The A2P Onboarding Documentation describes this process in detail (including specific guidance for ISVs). This applies equally to new Conversations as well as existing ones -- the A2P registration is done at the phone-number level.

        To reiterate: Any number of Messaging Services can direct traffic to the same Conversations Service without affecting the Conversations API.

        The impact to Phone Numbers is also specific to SMS and MMS traffic; A2P has no impact on WhatsApp or any other Messaging channel, so those channels don’t require any specific consideration for the above.

        You should consider the scale of your business: As advised above, if your business uses many Phone Numbers (more than 400, for example, which is the preset maximum size of a Messaging Service’s sender pool), you should consider distributing those numbers among several A2P Campaigns to benefit from multiple throughput caps.

        How does this affect Group Texting (i.e., Group MMS)?

        Group Texting, available via Conversations in the US and Canada, works over the MMS protocol (even when no image is exchanged) and thus is subject to MMS throughput limits. For now, carriers have not availed us of any specific throughput limitations for campaigns, so the Twilio account-level limit of 25 MPS for MMS messages applies to your Group Texting traffic.

        There is no limitation on how Twilio Phone Numbers can be combined with each other within Conversations, including having those numbers registered in multiple A2P campaigns (i.e., multiple messaging services). This also applies to group texting: any number of A2P campaigns can appear among the phone numbers in a group text.

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