How to sell with SMS and WhatsApp without annoying your customers

Text messages get read. That is exactly why they are so easy to abuse, and why US law and the phone carriers treat marketing texts more strictly than almost any other channel. Done well, SMS and chat apps bring back repeat customers at a low cost. Done badly, they bring opt-outs, spam filtering and legal risk.

This guide covers the consent rules, the habits that keep customers from tuning you out, and how to use WhatsApp for the customers who already prefer it.

This is general information, not legal advice. Messaging rules change and some states add their own. Talk to an attorney if you plan to text customers at scale.

Which channel for what

Channel	SMS	WhatsApp	Email
Best for	Short, time-sensitive messages: shipping updates, restocks, last-call offers	Two-way conversations with customers who already use WhatsApp	Longer content: launches, stories, gift guides, receipts
Who uses it	Almost every phone	Popular with some customers, not everyone	Almost every customer
Main US rules	TCPA, carrier rules (10DLC registration)	Meta’s business policies, plus general consent rules	CAN-SPAM
Opt-out	Reply STOP	Block, or ask to stop	Unsubscribe link

Most stores use all three: email as the backbone, SMS for a few high-value moments, and chat (Instagram DMs, Facebook Messenger, WhatsApp) for answering questions and closing orders.

Under the federal Telephone Consumer Protection Act (TCPA), marketing texts sent with automated systems generally require the customer’s prior express written consent. That means a clear, affirmative opt-in that tells the customer:

Who will text them (your store name)
That the texts are marketing messages, sent using automated technology
Roughly how often, and that message and data rates may apply
That consent is not a condition of buying
How to opt out (reply STOP) and get help (reply HELP)

Good ways to collect it:

An unchecked checkbox at checkout with that disclosure next to it
A sign-up form on your site, with a confirmation text the customer replies to
A keyword customers text to your number from a sign in your shop or on your packaging (“Text JOIN to…”)

Keep a record of when and how each person agreed. Order updates about a purchase the customer made are treated differently from marketing, but it is still good practice to ask before you text.

Separately, US mobile carriers require businesses texting from standard local numbers to register their brand and campaigns (known as 10DLC registration), usually through your messaging provider. Unregistered traffic can be filtered or blocked.

Opt-out: honor STOP right away

Every marketing text should make it easy to leave. Customers who reply STOP, UNSUBSCRIBE, CANCEL, END or QUIT should be removed promptly, with one confirmation text and nothing after that. Carriers and regulators watch opt-out handling closely, and a customer who cannot get you to stop is the customer most likely to complain.

Quiet hours

Federal rules restrict telemarketing to the hours between 8 a.m. and 9 p.m. in the recipient’s local time, and some states set narrower windows or limit how many messages you can send in a day. The simple habit: schedule texts for daytime in each customer’s time zone, and never send marketing late at night or early in the morning.

Email: CAN-SPAM basics

Email is less strict about opt-in than SMS under federal law, but CAN-SPAM still sets clear rules for commercial email:

Honest “From” names and subject lines
Identify the message as an ad where it is one
Include a valid physical postal address for your business
A clear way to unsubscribe, honored within 10 business days

Sending only to people who opted in is still the best policy. It protects your sender reputation, which decides whether your emails land in the inbox.

WhatsApp: for the customers who already use it

WhatsApp is not the default chat app for most US shoppers, but it is popular with some customers and communities, and with international buyers. If your customers message you there, meet them there.

WhatsApp Business app: free, on your phone, fine when you answer a few dozen chats yourself.
WhatsApp Business Platform: used through software, so several people can reply, order updates go out automatically and you can send approved template messages to customers who opted in. Meta charges per template message, by category and country; check Meta’s current pricing page.

Meta’s business policies require opt-in before you message people, and an easy way to stop. Blocks and reports lower your quality rating on the Platform, which can limit how many people you can reach.

Message etiquette

A few rules that keep customers glad to hear from you, on any channel:

Send less than you want to. As a rule of thumb, a few marketing texts a month is plenty for most stores. Order updates do not count.
Make each message worth opening: a restock of something they asked about, a real offer, a shipping cutoff reminder before the holidays.
Segment. Do not send a men’s launch to everyone who once bought a scarf. Use what they bought, when and how much they spend.
Keep it short. Store name first, one line of news, one link.
One clear action: a product link or “reply YES to reserve one”.
Watch the opt-outs. If more people leave after a send, you are sending too often or to the wrong group.

Turning chats into paid orders

The fastest way to lose an order in a chat is “I’ll send you a link later”. Close it in the same conversation:

Send a cart or order summary with items, price, shipping and total.
Share a checkout link so the customer can pay by card, Apple Pay or Google Pay without leaving the conversation for long.
Confirm the shipping address in the same message.
Send the order confirmation automatically once payment arrives.

Organize the inbox

Once a few people are replying, you need structure:

Labels such as New question, Awaiting payment, Paid, Shipped, Issue
Quick replies for your most common questions: delivery time, returns, sizes
Assign chats so two people do not reply to the same customer
Link the chat to the order so anyone can see the history

Where AjVik fits

AjVik’s WhatsApp tools sync your product catalog, let you send a cart or checkout link inside the chat, and put WhatsApp, Instagram and live chat messages into one inbox for your team. WhatsApp broadcasts go only to opted-in customers and use prepaid messaging credits, so you see what you spend before you send. Email campaigns include unsubscribe handling. SMS broadcasts are in early access.

Whatever you use, the principle holds: messaging works for selling because it feels personal. Keep it that way.