Your customers carry their phones everywhere. That's either your greatest marketing opportunity or your fastest path to a class-action lawsuit — depending on how you approach it. SMS marketing boasts open rates that email can only dream about, but the channel comes with strict federal rules, short attention spans, and zero tolerance for spam. This guide walks you through both the craft and the compliance side of text message marketing so you can grow without the legal risk.

The legal layer: what you must know

Before you send a single text, understand the federal laws governing SMS marketing. Ignorance is not a defense — and violations can result in fines of hundreds of thousands of dollars, or class-action suits.

Consent: what actually counts

A customer giving you their phone number at checkout is not consent to market to them. Consent must be:

• Express and written — a checked checkbox (not pre-checked), a signed form, or a keyword opt-in text
• Specific to your business — they agreed to receive texts from you, not a generic "marketing partners" clause
• Clearly informed — the opt-in language must state message frequency and that message/data rates may apply
• Not assumed from a transaction — purchasing from you, calling you, or giving you a business card is not consent to marketing texts

Crafting the message: less is everything

SMS is the most intimate digital channel in marketing. It arrives in the same inbox as texts from your customer's mom, their doctor, and their best friend. Treat that access with respect — and precision.

Length: the 160-character discipline

A single SMS segment is 160 characters. Go over that and carriers split your message into multiple segments — which costs more, sometimes arrives out of order, and can look sloppy. Most platforms support multi-part messages up to 1,600 characters, but the sweet spot for conversion is under 160 characters for the core message, with a second segment only if necessary for a URL or legal copy.

Tone and voice

SMS is a conversational medium. Don't write like a press release or a coupon flyer. Write like a knowledgeable friend who happens to run a business you love. Short sentences. Active voice. Real words, not marketing jargon.

Frequency and timing: the unwritten rules

TCPA tells you the hard floor (8 AM–9 PM recipient time). Best practice sets a much higher bar. The single fastest way to tank your SMS list is to text too often with too little value.

How often should you text?

For most businesses, 2–4 messages per month is the sweet spot. Retail and e-commerce brands with strong promotional calendars can push 6–8 during peak seasons (holiday, back-to-school) without significant opt-out spikes — but only if each message delivers real value. Service-based businesses, professional services, and B2B companies should generally stay closer to 2 per month.

Best times to send

General benchmarks put Tuesday through Thursday, between 10 AM and 12 PM or 5 PM and 7 PM (recipient's local time), as the highest-engagement windows. That said, your specific audience may vary significantly — test and track response rates by day/time using your SMS platform's analytics.

Avoid early mornings (before 9 AM), late evenings (after 8 PM), and early Sunday mornings. These windows don't just underperform — they actively annoy.

What to actually text: message types that work

Not all SMS messages are promotional. The best SMS programs blend multiple message types so customers see your texts as useful, not just commercial.

High-performing SMS content categories

• Flash sales and time-limited offers — SMS's time-sensitive nature makes it the perfect channel for offers expiring in 24–48 hours. Include exact end time and date.
• Appointment reminders and confirmations — among the highest-value messages you can send. Customers appreciate them, no-show rates drop, and it builds positive brand association with your texts.
• Order and shipping updates — transactional texts have near-100% read rates. Even when not marketing, these reinforce your brand and create good habits around opening your texts.
• Loyalty and VIP exclusives — reward your text subscribers with genuinely exclusive offers that aren't available through email or social. This justifies their opt-in.
• Event announcements and seat alerts — sold-out notifications, event day reminders, and last-call registrations drive immediate action better on SMS than any other channel.
• Two-way conversations — invite replies. "What's your biggest challenge with X? Reply and we'll send a resource." Engagement and list health both improve.
• Survey and feedback requests — short one-question surveys via text ("Rate your visit 1–5") get response rates 5–10x higher than email surveys.

Technical setup: do this before you send anything

10DLC registration

If you're sending commercial SMS in the United States, you must register your business and your messaging campaigns with The Campaign Registry (TCR) through your SMS platform. This process — called 10DLC registration (ten-digit long code) — is required by all major US carriers (AT&T, Verizon, T-Mobile). Unregistered numbers face increasing message filtering and eventual blocking.

Short codes vs. long codes vs. toll-free numbers

• Short codes (5–6 digit numbers like 74689) have the highest throughput and carrier trust — ideal for high-volume broadcast campaigns. They're also the most expensive ($500–$1,000/month).
• 10DLC long codes are standard 10-digit numbers that look like a local phone number — they're cost-effective for small and mid-sized businesses sending under 10,000 messages/month.
• Toll-free numbers (e.g., 1-800 numbers) sit between the two and are well-suited for customer service conversations.

Link tracking

Always use links built on your own domain or a branded short domain. Generic URL shorteners like bit.ly are increasingly flagged by carrier spam filters and signal to recipients that the message may not be legitimate. Most SMS platforms generate branded tracking links automatically.

Building your list the right way

A compliant, engaged SMS list is worth far more than a large but untargeted one. Quality over quantity isn't just ethical — it's commercially smarter.

Effective opt-in tactics

The best opt-in methods make the value exchange crystal-clear. Someone should never feel surprised that they're subscribing to your texts. Strong opt-in tactics include:

Keyword opt-in: "Text DEALS to 55512 to get exclusive offers every week." Simple, trackable, and proves intent.
Web sign-up form: A standalone form — not buried in checkout — with explicit language about what they're signing up for.
In-store sign-up: A paper form or tablet sign-up with clear disclosure, or a QR code linking to your opt-in landing page.
Double opt-in: After they subscribe, send a confirmation text requiring a reply before adding them to your list. Reduces wrong numbers, bots, and future spam complaints.

The pre-send checklist

Before every campaign hits send, walk through these items:

• Does the message identify your business by name within the first 30 characters?
• Is the offer or information specific and genuinely valuable to the recipient?
• Is there one clear call to action — and only one?
• Does the message include "Reply STOP to unsubscribe" or equivalent language?
• Is the send time between 8 AM and 9 PM in every recipient's time zone?
• Have you segmented out anyone who has not explicitly opted in?
• Is your link branded and functional? (Test it on mobile.)
• Is the character count under 160 for the core message?
• Has this been tested on at least one real device before deployment?
• Is your opt-out suppression list current and integrated with your platform?