SMS marketing is sending promotional and service text messages to customers who have agreed to receive them, usually in bulk from a messaging platform or API. To start, you need four things: recorded consent, a clean list of numbers, a sender ID that is allowed in each country you text, and short messages with one clear action and an easy way to opt out.
This guide walks through each step in the order you will meet it: consent and list building, sender IDs, writing and personalising messages, timing, measurement, opt-outs and cost. If you already know the basics and want to see the tools, our SMS marketing platform page shows how campaigns are built and sent.
What is SMS marketing and why do businesses use it?
SMS marketing covers any text that promotes your business: offers, launches, loyalty rewards, event invitations and win-back messages. Most programmes also send service texts, such as order updates and reminders, from the same platform, because customers who find those useful are more likely to stay subscribed to the promotions.
Businesses of every size use it for the same practical reasons:
- Reach. Almost everyone has a phone that receives texts. GSMA Intelligence’s The Mobile Economy 2026 report counts 5.8 billion unique mobile subscribers, around 70% of the world’s population. In the US, Pew Research Center’s mobile fact sheet (survey fielded February to June 2025, published November 2025) found that 98% of adults own a cellphone.
- No app needed. A text lands in the phone’s native inbox, on a basic handset or a smartphone, with no install, login or follower count.
- Speed. A text is delivered within seconds on a good route, which suits flash sales, same-day offers and last-minute changes.
- Low entry cost. You pay per message, so a small business can start with a few hundred contacts and grow from there. There is no creative production or media buying.
- It is measurable. With tracked short links and delivery reports you can see what was delivered, who clicked and who opted out, per campaign.
SMS also has limits. You have 160 characters for a standard message, each text has a cost, and the consent rules are stricter than for most channels. You will often see claims such as “98% of texts are opened”. We have not found a primary source for that figure, so we do not rely on it; measure your own clicks, replies and sales instead.
Which texts count as marketing and which are transactional?
The difference decides which rules apply, so sort your planned messages before you build a list.
| Type | Examples | Consent needed? |
|---|---|---|
| Marketing (promotional) | Discounts, launches, newsletters, win-back offers, event invitations | Yes, prior consent (or the soft opt-in for existing customers in the UK and EU). Every message needs an opt-out. |
| Transactional (service) | Order and delivery updates, booking confirmations, appointment reminders, payment alerts | Usually covered by the service the customer asked for, as long as the text does not promote anything |
| Authentication | One-time passcodes and login alerts | Covered by the action the user took; never add marketing to these |
If you add an offer to a delivery update, it becomes a marketing message. Our SMS marketing compliance guide covers GDPR, the ePrivacy rules, the UK’s PECR and country-specific rules in detail.
How do you get consent and build an SMS list?
A good list is the biggest single factor in campaign results. People who asked for your texts click; people who did not complain, opt out or report you as spam, which hurts delivery for everyone on your sender ID.
Ways to collect numbers with consent:
- Checkout and account forms. Add a separate, unticked box for texts, next to the email box rather than inside your terms.
- A keyword to your number. “Text JOIN to” a virtual number works well on posters, packaging, receipts and radio, because the reply is the opt-in.
- In store or at events. A tablet form or QR code at the till or stand, with the same wording as online.
- Your website. A pop-up or footer form offering something specific, such as early access to sales.
For every contact, record when and where they joined, and the exact wording they agreed to. Tell people what they will get and how often (“up to four texts a month with offers and new arrivals”), and send a confirmation straight away:
[Brand]: You’re subscribed to texts with offers and new arrivals, up to 4 a month. Reply STOP to opt out.
Three rules protect the list once you have it. Never buy or rent lists, because the consent does not transfer to you. Store numbers in international format (+44…, +357…), which prevents failed sends caused by missing country codes. And check numbers before large campaigns: an HLR lookup shows whether a number is active and which network it is on now, so you stop paying for texts to dead lines. Our guide to HLR and MNP checks explains how.
Which sender ID should you use?
The sender is what the customer sees at the top of the message, and the rules for it are set country by country.
- Alphanumeric sender ID: your brand name, up to 11 characters, such as “YourShop”. It builds recognition, but an alphanumeric sender ID is one-way: customers cannot reply to it.
- Virtual mobile number (long code): a real number that can send and receive, needed for keyword opt-ins, surveys and replies.
- Short code or toll-free number: used in some markets, notably the US and Canada, for high-volume or regulated traffic.
More countries now require registration before you send. Our sender ID requirements by country list is the quickest check. A few examples:
- United Kingdom: brand names are accepted and are registered with us before live traffic. See bulk SMS in the United Kingdom.
- Spain: the CNMC confirmed that from 15 September 2026 messages with unregistered aliases are blocked. See SMS to Spain.
- India: sending under your own header requires registering your entity, headers and templates on DLT, as TRAI’s advice to senders sets out. See bulk SMS in India.
- United States: alphanumeric senders are not supported, so you send from a registered toll-free number, a 10DLC number or a short code. See SMS to the United States.
Check each market before launch, because an unregistered sender can be blocked or replaced with a number your customers do not recognise.
How do you write an SMS marketing message that works?
Most good marketing texts follow the same pattern:
- Who it is from. Start with your brand name, even when the sender ID already shows it, because some phones display the number instead.
- One offer. One product, one discount or one piece of news per message.
- A reason to act now. A date, a time or a limited quantity.
- One link or one reply keyword. Not both, and never two links.
- The opt-out. Short and clear at the end.
[Brand]: 20% off all knitwear until Sunday midnight. Shop now: [link] Reply STOP to opt out
Length matters because it sets the price. A single SMS holds 160 characters in the GSM-7 alphabet. Use one character outside it, such as an emoji, a curly apostrophe copied from a word processor or some accented letters, and the whole message switches to Unicode, where the limit is 70 characters. Longer texts are split into a concatenated SMS of 153 characters per part (67 in Unicode), and each part is billed. Paste drafts into our SMS length calculator before you schedule.
A few more habits help. Write in plain sentences rather than capitals and exclamation marks, which read like spam and can be filtered. Use a short link rather than a long URL, and prefer a platform or branded short link over a public shortener, because some carriers filter the generic shorteners that spammers use. When you send a reminder for the same campaign, change the wording: the same text twice feels automated and prompts opt-outs.
How do you personalise texts with mail merge?
Mail merge replaces tags in your text with each contact’s own data at the moment of sending. In SMS.to’s message editor you can use up to five dynamic tags per message, such as {name} and {surname}, plus custom tags such as {custom1} and {custom2} that you fill from your contact list.
[Brand]: Hi {name}, your {custom1} points expire on 30 June. Use them in store or online: [link] Reply STOP to opt out
Five practical uses:
- A first-name greeting on offers and reminders.
- Loyalty balances or tiers in a custom field, with the expiry date.
- The customer’s nearest branch, so a store event reaches the right town.
- The last category bought, so a sale message leads with shoes for shoe buyers.
- Booking details, such as a date and time, in service texts.
Two cautions. Check the longest value in each field, because a long name can push a 158-character message into two parts. And fill blanks before sending, since “Hi , your points” looks broken. Keep sensitive details, such as health or account information, out of marketing texts entirely.
When is the best time to send marketing texts?
Send in the recipient’s local time, not yours, and stay within legal hours where they exist. In the US, the FCC’s rules at 47 CFR 64.1200(c)(1) bar telephone solicitations before 8am or after 9pm at the called party’s location. In the United Arab Emirates, the TDRA’s spam regulatory policy (article 8.3) bans marketing texts between 9pm and 7am (see SMS to the UAE). Where no law applies, treat early morning and late evening as off limits anyway.
Within those limits, test rather than guess. Late morning, lunchtime and early evening are good starting points for consumer offers, and business-to-business texts usually work best in office hours. Split a campaign between two send times, compare clicks, and keep the winner as your default. When you send through the API, you can schedule each batch in the recipient’s time zone.
Frequency matters as much as timing. Keep to the rate you promised at sign-up, and watch the opt-out rate after each send: a jump usually means the message was irrelevant or too frequent.
How do you measure SMS marketing results?
| Metric | What it tells you | Where it comes from |
|---|---|---|
| Delivery rate | Share of sent messages that reached handsets; a drop points to bad numbers, a blocked sender or a route issue | Delivery reports (DLRs) |
| Click-through rate (CTR) | Share of delivered messages whose link was clicked | Tracked short links |
| Conversion rate | Orders, bookings or sign-ups per click | Your shop or CRM, with campaign tags on the landing URL |
| Opt-out rate | How many people left after this send | Opt-out reports |
| Replies | Answers to a keyword or question | Two-way number inbox or webhook |
| Cost per conversion | Campaign cost divided by conversions; the number to compare with other channels | Your spend and sales data |
Change one thing at a time when you test: the offer, the wording, the send time or the audience. With SMS.to shortlinks you can split a campaign, compare CTR between versions, and see the subset of people who clicked, with the time and device of each click, so you can follow up with the most engaged contacts.
How do opt-outs work in SMS marketing?
Every marketing text must give the recipient a simple, free way to stop further messages, and you must honour it promptly. There are two common methods. “Reply STOP” works when you send from a number that can receive replies. With an alphanumeric sender ID nobody can reply, so you need an opt-out link instead. On SMS.to, adding the tag STOPSMS {optout} to your message inserts a short link on the nosmsto.me domain; people who use it are removed from your future campaigns, and they are skipped, at no charge, on later sends.
Keep opted-out numbers on a suppression list, even if you delete the rest of their data, so they are not re-imported from another source by mistake.
How much does SMS marketing cost?
You pay per message part delivered to the network, and the price depends on the destination country and your volume. SMS.to’s pricing page shows rates from $0.023 per SMS, varying by country, on a pay-as-you-go basis with volume discounts and no setup fees. Your real cost per campaign depends on three things you control: message length (two parts cost twice as much), encoding (Unicode shortens each part) and list quality (invalid numbers still cost money). Our guide to SMS pricing and character limits explains the arithmetic.
What should you check before your first campaign?
- Every contact has a recorded opt-in, or qualifies for the soft opt-in where that applies.
- Numbers are in international format and recently checked.
- The sender ID is registered or approved in each destination country.
- The message fits one part, or you have accepted the cost of two.
- The link works on a phone and the landing page matches the offer.
- The opt-out line is present and tested.
- The send time is inside legal hours in each recipient’s time zone.
- You have sent a test to a few colleagues on different networks.
How SMS.to handles SMS marketing
SMS.to is operated by Intergo Telecom, a licensed telecom and CPaaS operator that has been building messaging infrastructure since 2014. The SMS.to features used most in marketing programmes are:
- Contacts and lists: import a CSV or paste numbers, then organise lists and tags for segments.
- Mail merge: up to five dynamic tags per message, including {name}, {surname} and custom fields.
- Shortlinks with CTR: tracked links for A/B tests, with click time and device data.
- Opt-out tools: the one-click nosmsto.me opt-out link, with opted-out numbers skipped on later sends.
- Two-way SMS: rent virtual mobile numbers to use as a sender or to collect replies, keywords and survey answers.
- Long codes and short codes: virtual mobile or toll-free numbers for sending and receiving where available.
- Team members: invite colleagues under one account, allocate sending credits and set access levels.
- API and scheduling: trigger texts from your shop or CRM, or schedule batches by time zone.
We also guide you on sender ID registration and local rules for each market before you launch. See the SMS.to marketing platform for a walkthrough of a first campaign.
FAQs
Is SMS marketing legal?
Yes, when you have the recipient’s prior consent (or, in the UK and EU, the soft opt-in for existing customers), identify yourself and offer a free, simple opt-out in every message. Some countries add sender registration and permitted sending hours.
How many marketing texts should I send each month?
Send only as many as you promised at sign-up. Many brands start with two to four a month and adjust based on opt-out and click rates.
Can customers reply to my marketing texts?
Only if you send from a number that can receive messages, such as a rented virtual mobile number. Alphanumeric sender IDs are one-way.
How long can a marketing text be?
160 characters for one GSM-7 message, or 70 if it contains Unicode characters such as emoji. Longer messages are split and each part is charged.
Do I need a developer to start?
No. You can import contacts and send campaigns from the web platform. The API is there when you want to trigger texts from your own systems.
Ready to send your first campaign? Create a free account, no credit card needed, import a test list and send yourself a message in a few minutes.
