Most of the marketing you send goes somewhere people have learned to skim. Promotions tabs, social feeds, mailboxes full of flyers. A text message lands somewhere people check constantly: the same screen where their friends and family reach them. That is the whole appeal of SMS marketing, and it is also the reason the rules around it are strict.
This guide covers what SMS marketing is, how a text actually gets from your business to a customer's phone, why it tends to outperform other channels, what it costs (with real math), and where WhatsApp is a better choice. We make Ready, an SMS platform, so we'll point out where our product fits. We'll also say plainly where it doesn't.
What SMS marketing actually is
SMS marketing is sending text messages to customers who have agreed to hear from you. Those messages promote, remind or inform. "SMS" stands for Short Message Service, the plain text format every mobile phone supports. You don't need an app, a data connection or a smartphone.
It usually falls into two buckets:
- Promotional messages: sales, new products, event invites, "we have openings this week."
- Transactional or informational messages: appointment reminders, order updates, delivery windows, review requests after a visit.
The line between them matters for how you register and what consent you need. We break it down in transactional vs promotional SMS. Most small businesses end up doing both. A salon sends reminders every day and a promo once or twice a month.
What SMS marketing is not: texting a purchased list of strangers. In the US, marketing texts need prior consent. Cold outreach belongs on the phone or in the mail, not in a text.
How a marketing text gets from you to a customer
Here is the path a message takes, in plain terms:
- You collect consent. A customer checks a box on your booking form, texts a keyword to your number, or signs up at the counter. The record of that opt-in (when, where, what wording they saw) is yours to keep. Our guide on what opt-in means for text messages covers what a good opt-in looks like.
- You get a business number and register it. Business texting from a regular 10-digit number in the US runs on A2P 10DLC. You register your brand and your campaign (what you'll send and why) with the carriers. Unregistered business traffic gets filtered, so this step is not optional in practice. Our 10DLC explainer walks through it.
- You write and send. Either one-to-one replies from an inbox, or a campaign to a segment of your list.
- Carriers deliver it. Your platform hands the message to carrier infrastructure, and the carrier passes it to the phone.
- The customer replies, or opts out. Replies come back into your inbox. A "STOP" reply has to be honored immediately and permanently.
What registration costs and how long it takes
On Ready, registration is handled in the app with no setup fee. The charge when you submit is the first month, $25. After that, the monthly cost is $25/mo for registration + $2 per number. Most approvals take 2 to 7 days. While you wait, an account can send up to 500 texts a month before registering, at the normal per-text rate.
Why SMS marketing works
There's no magic here. A few structural reasons explain why text tends to beat other channels for small businesses.
People actually see it
A text arrives with a notification on the lock screen. There is no promotions tab and no algorithm deciding whether to show it. Read rates for SMS are widely reported as very high. The exact figures vary by source, so treat any single number with caution. The practical point holds anyway: if a text is delivered, it almost always gets seen.
The list wants to hear from you
An SMS list is built on explicit consent, and people guard their phone numbers more closely than their email addresses. Someone who gives you their number is telling you something. Opted-in lists reply, and how much swings a lot with the offer and the audience.
Short forces clarity
One segment is 160 characters. You can't bury the offer under three paragraphs. "Two cancellations Thursday afternoon, reply YES to grab one" does more work than most email newsletters.
It's a conversation, not a broadcast
Customers reply to texts. They ask questions, confirm appointments and send photos. A two-way inbox turns a campaign into a stream of small conversations, and that is often where the sale actually happens.
Where it doesn't work
Texting too often, texting at 10 PM, texting people who never agreed to it, or sending vague "big sale!!" messages will burn a list fast. Opt-outs rise and carriers notice. SMS rewards restraint. For most businesses, two to four promotional texts a month is plenty.
What SMS marketing costs: a worked example
SMS is billed per segment, not per message. The rules:
- A plain-text message up to 160 characters is 1 segment. Longer messages split into segments of 153 characters each.
- One emoji (or other non-standard character) drops the limit to 70 characters per segment, or 67 when a message runs to multiple segments.
On Ready, the Standard rate is $0.0075 per segment plus a $0.0045 carrier fee, $0.012 a segment all-in, with the carrier fee itemized separately. Replies you receive are billed the same way as sent texts. See pricing for the current card.
Ready's all-in prices per segment include the carrier fee but not screening: Scrub lists and Number validation, the two switches in Settings under Compliance, each add $0.003 per segment when switched on, shown as screening on your bill, and both are off by default. Unless you turn the opt-out footer off, the first text to each contact, and one again from time to time, also gets "Reply STOP to opt out" and your business name if the message does not already have them, so a text close to the segment limit can bill one more segment.
Example assumptions: a local business with 2,000 opted-in contacts sends one monthly promo.
| Message | Segments each | Total segments | Ready rate | Carrier fees | Total |
|---|---|---|---|---|---|
| 140 characters, plain text | 1 | 2,000 | 2,000 × $0.0075 = $15 | 2,000 × $0.0045 = $9 | $24 |
| 175 characters with one emoji | 3 | 6,000 | 6,000 × $0.0075 = $45 | 6,000 × $0.0045 = $27 | $72 |
That emoji tripled the bill. The cheapest optimization in SMS marketing is editing: cut to 160 characters and drop the emoji unless it earns its place. Ready swaps curly quotes, long dashes and ellipses for plain ones before sending, so those characters won't quietly inflate your count.
Where Ready fits on price, honestly
Raw carrier APIs like Twilio (around $0.0083 per segment) and GoHighLevel's built-in LeadConnector phone (around $0.0083 per message, roughly $0.0128 all-in) cost less per message than Ready Standard. If per-message price is your only criterion and you have a developer, those are fine choices.
What Ready includes on top of the per-segment rate: in-app 10DLC registration, automatic STOP handling, quiet-hours enforcement, a two-way inbox, contacts, templates, bulk campaigns and an AI message writer. Compared with per-seat business texting tools or subscription plans, that bundle often works out favorably for small teams. Run your own numbers, though. Our SMS marketing pricing guide shows how to compare.
SMS vs WhatsApp for marketing
WhatsApp comes up a lot, and for some businesses it's the right answer. Here's how the two compare in practice:
| SMS | WhatsApp Business | |
|---|---|---|
| Reach | Every mobile phone, no app needed | Only people who have WhatsApp installed and use it |
| US usage | Universal default | Far less common in the US than in Latin America, Europe or India |
| Setup | Business number + 10DLC registration | Meta business verification + approved message templates |
| Content | Text (plus MMS for images) | Rich media, buttons, catalogs |
| Who starts | You can text first with consent | Marketing outside a customer-initiated window requires pre-approved templates |
| Pricing | Per segment | Meta's own pricing, which varies by country and message type |
Choose SMS if your customers are mostly in the US, your list spans every kind of phone, and you need reminders and promos to reach everyone.
Choose WhatsApp if your customers are international, or they already message you there. It also makes sense if you sell visually and want catalogs and buttons inside the chat.
Many businesses do both: SMS as the default and WhatsApp for the customers who prefer it. We go deeper in WhatsApp vs SMS marketing.
The compliance basics you can't skip
Under the TCPA, texting without proper consent can carry exposure of $500 to $1,500 per text. That adds up fast across a list. The good-practice checklist:
- Get consent and keep the record. Store when and how each person opted in.
- Identify yourself in the first message and include opt-out language ("Reply STOP to opt out").
- Honor STOP instantly. On Ready, opt-outs are handled automatically and apply across every campaign.
- Respect quiet hours. Ready holds sends outside permitted local hours based on the recipient's area and sends them later. Campaigns, drip campaigns and automations wait up to 24 hours for the window; a one-to-one or API text is held only if the window opens within 6 hours, otherwise it is refused and must be resent; a one-to-one reply to someone who texted you in the last 24 hours goes out at any hour.
- Scrub when it makes sense. Ready's litigator/DNC scrub screens known TCPA litigators and DNC complainers before a send.
None of this makes you lawsuit-proof. Compliance stays the sender's responsibility. These tools lower the risk, and they're what carriers expect from a legitimate sender.
Getting started without overthinking it
The practical takeaway: SMS marketing works because it reaches a screen people actually look at, and it goes to people who asked to hear from you. Keep messages short, send them sparingly, and treat consent as the foundation rather than a formality.
A sensible first month looks like this:
- Add an opt-in checkbox or keyword to the places customers already interact with you.
- Register your brand and campaign.
- Start with transactional texts, like reminders and confirmations.
- Add one promo a month once the list grows.
If you want to try Ready, the first 20 texts are free one-to-one sends. Use them to test your messages before you register, because the free texts end once a registration is paid for. Campaigns are billed from the first text, and to send any text you need a card and a number ($2 a month, the first month charged when you get it). You can sign up here whenever you're ready.