What do I need to legally text customers in the US?

Two things that people constantly merge into one. A2P 10DLC brand and campaign registration with the carriers, without which your messages are blocked outright rather than delayed. And consent that satisfies the TCPA, which for automated marketing texts to a mobile means prior express written consent. Registration without consent is unlawful sending; consent without registration is undelivered sending.

What is the biggest compliance mistake you see?

Assuming a past customer relationship substitutes for consent to automated texts. The established business relationship exemption applies to the Do Not Call Registry and covers live calls, not autodialed calls and texts. A bulk SMS campaign to former customers is exactly what it does not cover.

Is most published guidance on this reliable?

No, and that is not a rhetorical flourish. When we checked before publishing, the majority of current articles stated that the FCC one-to-one consent rule had taken effect in January 2026. It was vacated by a federal appeals court in January 2025. Check the date on anything you read, and prefer primary sources.

Reference

SMS Compliance for Service Businesses

Everything we had to learn to send text messages on behalf of partners without getting them blocked or sued.

Howard KanCo-founder and COO, Agency Logics

Spent 8 years running operations for a startup studio that launched more than a dozen companies. Leads CRM, automation, AI assistants, websites, and delivery infrastructure at Agency Logics.

Published September 1, 2026

The two systems, side by side

Carrier registration and federal consent law compared.
	A2P 10DLC	TCPA
Type	Carrier registration requirement	Federal law
Question	Will this message be delivered?	Were you allowed to send it?
Enforced by	Carriers and The Campaign Registry	The FCC, and private lawsuits
Failure mode	Messages silently blocked	Statutory damages per message
Fix time	Days, once you know the cause	Requires rebuilding consent records

Carrier registration and federal consent law compared.

The asymmetry is worth internalising. An A2P problem is annoying and fixable in days. A consent problem is expensive and often cannot be fixed retroactively at all, because you cannot go back and obtain consent you did not capture.

The guides

A2P 10DLC: why your texts are being blockedThe two registration layers, realistic timelines, and why this is a gate rather than a task.Registering A2P 10DLC in GoHighLevelThe Trust Center walkthrough and the four fields that decide whether you are approved.What A2P 10DLC actually costsBrand vetting, campaign fees, monthly charges, and the per-message carrier surcharge.Why campaigns get rejectedThree causes, the consent language that passes, and how to diagnose before resubmitting.Can you legally text old leads?The corrected TCPA position, including the rule almost everyone reports as being in force that was struck down.Compliance trackerDated log of what changed, what is in force, and the deadlines coming in October 2026 and January 2027.

The order to do this in

If you are starting from nothing and want to run an SMS programme, the sequence that avoids wasted work is:

Register the brand first, because it is quick and everything else waits on it. Add consent language to your forms next, because the campaign registration will be checked against it. Audit what consent you already hold for existing contacts before you plan any send to them, because that determines who can receive what. Then submit the campaign and use the review window to build the sequence. Then send.

Most people do this in the opposite order, build the campaign, then discover at send time that they are not registered and that half the list cannot lawfully be messaged. That is a two-week delay created entirely by sequencing. It is the reason registration is the first gate on every database reactivation project we run.

Common questions

What do I need to legally text customers in the US?: Two things that people constantly merge into one. A2P 10DLC brand and campaign registration with the carriers, without which your messages are blocked outright rather than delayed. And consent that satisfies the TCPA, which for automated marketing texts to a mobile means prior express written consent. Registration without consent is unlawful sending; consent without registration is undelivered sending.
What is the biggest compliance mistake you see?: Assuming a past customer relationship substitutes for consent to automated texts. The established business relationship exemption applies to the Do Not Call Registry and covers live calls, not autodialed calls and texts. A bulk SMS campaign to former customers is exactly what it does not cover.
Is most published guidance on this reliable?: No, and that is not a rhetorical flourish. When we checked before publishing, the majority of current articles stated that the FCC one-to-one consent rule had taken effect in January 2026. It was vacated by a federal appeals court in January 2025. Check the date on anything you read, and prefer primary sources.

Sources

Get the compliance layer built once, properly

Registration, consent language, list segmentation by consent origin, and opt-out routing back to the CRM. It is a finite piece of work, and it is the foundation every SMS campaign after it depends on.

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