Is a phone number given at checkout consent to text marketing?

Only if the checkout said so and the box was not pre-ticked. A number supplied to complete an order is consent for order messages. Marketing needs its own clear statement, and the safest pattern is a separate unticked box that names text messages.

Can I text people who have not opted in if they are businesses?

Rules differ by country, and business numbers are not automatically exempt. Even where a legitimate interest argument exists, carriers enforce their own standards on top, and a list without consent fails commercially before it fails legally.

How fast must a stop request be honoured?

Immediately, in practice. The technical standard is that the next send must not include that number, which means the suppression list has to be consulted at send time. A daily batch job that processes stops overnight will send to someone who has already asked you twice to stop.

Do quiet hours apply to transactional texts?

Transactional messages such as a delivery confirmation are usually treated differently from marketing, and they can be sent when they are needed. A message promoting something is marketing even if it arrives during a transaction, so the distinction is the content, not the timing.

SMS Consent: The Five Things Carriers Check Before Your Text Lands

The short answer

To text people legally and reliably you need a documented opt-in, a message that identifies the sender, a keyword that stops future messages, honoured immediately, and sending that respects quiet hours. Carriers enforce these through number registration and filtering, so an unchecked list fails quietly rather than with an error.

Email tolerates a certain amount of bad practice before anything visible happens. SMS does not. Messages are routed through carriers who filter by sender reputation and by whether the traffic looks like it belongs on a registered number, and they will simply drop or block traffic that does not. That is why the checklist below is short and why every item has to be true before the first campaign, not after the first complaint.

One: consent, with a record you can produce

Store the number with the date, the source and the exact wording the person agreed to. "Signed up on the website" is not a record; the sentence they read is. When a recipient complains, the first question is what they agreed to, and an answer of "we think they opted in" ends the conversation badly.

Never mix purposes. A number given for a delivery notification is not consent for marketing, and a number collected on a paper form at an event needs the same care as one collected digitally. If the form did not say marketing, do not market to it.

Two: identify yourself in the message

Every marketing message should name the sender, because a recipient who does not recognise the brand blocks instead of reading. Ten characters at the start of the message costs nothing and prevents the most common complaint: "who is this".

Identify the list too. "You signed up at our March workshop" or "you asked for release updates" turns an unexplained text into a message the recipient can place, and it is also the sentence that makes the opt-out feel reasonable rather than arbitrary.

Three: a stop keyword that works immediately

A single-word stop instruction, honoured across every list, is the difference between a complaint and a quiet removal. The keyword should be stated in the message, work without a login, and be processed by the sending system rather than by a person reading an inbox later.

The mechanism has to be central. If one campaign sends through one tool and another through a spreadsheet, a stop from the first campaign will not suppress the second, and that is the failure that produces a carrier complaint rather than a customer complaint.

Four and five: quiet hours and message frequency

Text messages arrive with a sound, so timing is part of consent in a way it is not for email. Sending at 2am is legal in some places and a guaranteed complaint in all of them. Keep sends inside a normal waking day in the recipient's time zone, which also means segmenting a list by region rather than treating it as one audience.

Frequency is the other half. A list that receives a message every week for a month produces opt-outs that look like a consent problem and are actually a pacing problem. Decide how often the list hears from you, tell them at the point of sign-up, and keep to it.

Worked example: the opt-out that did not carry across

A small venue collects numbers on a sign-up card at events and sends a weekly listing by text. The first three weeks produce steady replies. In week four, two recipients complain that they had already replied STOP twice.

The cause was structural: the sign-up cards were entered into the booking system, while week four's campaign was sent from a separate spreadsheet exported earlier. The STOP replies had been processed in the sending tool, which kept its own suppression list, and the spreadsheet knew nothing about them.

The fix cost nothing: one suppression list, applied at the moment of sending to whichever list is being used, with a check that refuses a send if the suppression source is unavailable. Nothing about the messages changed. The complaint was never about the content; it was about being ignored twice.

What each requirement looks like in practice

Requirement	What carriers or rules expect	How it fails	The fix
Documented opt-in	Date, source and wording for every number	Complaints and blocked traffic	Capture the wording at the point of collection
Sender identity	The brand named in the message	Recipients block or report	Lead with your name in ten characters
Stop instruction	A keyword that stops all future messages	Carrier complaints, filtering	Central suppression applied at send time
Quiet hours	No messages outside a normal day	Opt-outs, complaints, filtering	Segment by time zone and schedule
Frequency	What the recipient was told to expect	Opt-outs that look like consent failure	Write the frequency down and keep to it
Registered sender	A registered number or sender ID for the route	Delivery fails silently	Complete registration before the first campaign

Each row is enforced somewhere other than your own dashboard, which is why a campaign can look successful and reach nobody.

Before the first text goes out

1Every number has a stored date, source and the wording the person agreed to.
2The wording mentions text messages and marketing specifically, not "updates" in general.
3The sender is identified in the first line of every message.
4A stop keyword is stated in the message and processed automatically.
5Suppression is central and checked at send time, not at import time.
6Sending is limited to a normal waking day in the recipient's time zone.
7The frequency matches what people were told to expect.
8The sender number or ID is registered for the route you are using.
9A complaint has a named owner and a documented response.
10A test send is made to your own phone before the list, including the opt-out path.

Where this connects on this site

Sends with a central suppression list run from the SMS sending tools on this site
For the messaging side of the same audience, see the WhatsApp channel and its consent rules
Recording the wording starts with collecting consent at the point of capture

What this will not do

This page is not legal advice. Consent rules, quiet hours and registration requirements differ by country and change.
No checklist guarantees delivery: carriers filter by sender reputation and traffic patterns that a sender cannot see.
Documented consent does not permit content the recipient did not expect. A delivery-update opt-in does not become marketing permission.
Message frequency and stop keywords do not remove the need for the number or sender ID to be registered for the route in use.
Nothing here promises that a campaign will reach a given number of people, and any delivery percentage would be invented.

Questions this page gets asked

Is a phone number given at checkout consent to text marketing?: Only if the checkout said so and the box was not pre-ticked. A number supplied to complete an order is consent for order messages. Marketing needs its own clear statement, and the safest pattern is a separate unticked box that names text messages.
Can I text people who have not opted in if they are businesses?: Rules differ by country, and business numbers are not automatically exempt. Even where a legitimate interest argument exists, carriers enforce their own standards on top, and a list without consent fails commercially before it fails legally.
How fast must a stop request be honoured?: Immediately, in practice. The technical standard is that the next send must not include that number, which means the suppression list has to be consulted at send time. A daily batch job that processes stops overnight will send to someone who has already asked you twice to stop.
Do quiet hours apply to transactional texts?: Transactional messages such as a delivery confirmation are usually treated differently from marketing, and they can be sent when they are needed. A message promoting something is marketing even if it arrives during a transaction, so the distinction is the content, not the timing.

Last reviewed 2026-10-26. Written for readers in the United States and elsewhere; rules about access, email and consent differ by country, and nothing on this page is legal advice.