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SMS is the highest-engagement outreach channel for political campaigns. Culper handles the compliance infrastructure so you can focus on the message.

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What is A2P 10DLC?

A2P (Application-to-Person) 10DLC is the carrier registration system for sending campaign text messages from a 10-digit long code (a regular-looking phone number). Without it, carriers will block your messages.

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Setup: connect a registration

Open SMS in the dashboard. Until a registration is connected, the page shows two choices.
  • Register New Service. A two-step form collects your brand (organization name, contact details, optional EIN and website, how you will use SMS) and your campaign (two sample messages, your opt-in workflow, and your STOP and HELP replies). Approval comes from The Campaign Registry and Twilio and can take days to weeks.
  • Connect Existing Service. If your organization already has an approved Twilio messaging service, connect it here. You can also ask Culper support to connect it for you from Get Help.
Culper checks your registration with Twilio every time the SMS page loads, and again before every send. The New SMS campaign button stays off until the registration is verified.
You must not send campaign texts until A2P registration is approved. Carriers will filter/block unregistered political messages, and you may be flagged for violations.

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TCPA compliance

Every SMS you send must comply with the Telephone Consumer Protection Act (TCPA):
  • Prior express written consent is required for each voter you text
  • All STOP replies are honored immediately and automatically
  • Opt-outs are added to a global suppression list — they cannot be overridden per campaign
  • Culper adds consent language to your opt-in flows automatically
Political campaign texting without documented consent is one of the most common causes of TCPA lawsuits. Text only people who opted in the way your registration describes. Culper’s suppression system is non-optional — never attempt to work around it.

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Sending a text blast

Once your registration is verified:
  1. Go to SMS and click New SMS campaign
  2. Name the campaign and pick a saved voter list
  3. Write your message and say who it’s from. The preview shows exactly what voters get and how many segments it uses
  4. Send a test to your own phone (up to five numbers)
  5. Review the summary and click Launch SMS campaign
What happens when you launch:
  • One text per phone number. When several voters on the list share a number, it gets one text.
  • Texting hours. Texts go out between 9am and 8pm in each voter’s time zone. Anything still waiting at 8pm goes out from 9am the next day. The campaign shows when it resumes.
  • Opt-out line. If your message doesn’t mention STOP, Culper adds “Reply STOP to opt out.” to the end.
  • Voters who are no longer on the current county roll, and numbers on the suppression list, are skipped.
A message over 160 characters is sent as two or more segments, and each segment is billed and counted against carrier limits. Keep messages short.

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Carrier limits on low-volume registrations

Some registrations are approved as low volume. If yours is, the confirm step says so before you launch.
  • Carriers allow fewer than 2,000 texts a day to T-Mobile customers, shared with anything else sent under the same registration
  • AT&T delivers about 75 texts a minute
  • Large lists are slow, and texts to T-Mobile customers past the daily limit fail
Keep each day’s sends to a few thousand people. If you need more, ask Culper support about a larger registration.

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Personalization

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One-to-one texting (P2P)

For conversations, where a texter sends each message and reads the replies, use P2P texting. It sends on the same registration and number.

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Door-follow SMS

From the mobile walk app, volunteers can send an immediate follow-up text to a voter who wasn’t home. This uses the same A2P registration and suppression list.

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Opt-out handling

When a voter replies STOP, UNSUBSCRIBE, CANCEL, END, or QUIT:
  • They are immediately added to the global suppression list
  • Future campaigns cannot text them, from any campaign in Culper
  • You can see the opt-out count in each campaign’s stats