SMS marketing: what it is, examples, rules and how to start

What is SMS marketing?

SMS marketing is the practice of sending promotional and informational text messages to people who have agreed to receive them. A shop texts a discount code, a clinic reminds patients about an appointment, a delivery brand tells you the parcel is out. It is one of the oldest digital marketing channels and still one of the most direct: the message lands on the phone in someone's hand, usually within seconds.

That directness is also the risk. A text feels personal, so an unwanted one irritates more than an unwanted email, and regulators agree. This guide covers how SMS marketing works, the consent rules that matter in the markets we serve, what good messages look like, and how to measure results honestly. If you are new to sending, start with the SMS gateway guide.

SMS marketing vs transactional SMS

Mixing the two is the most common mistake. An order confirmation that ends with a sale banner is promotional in the eyes of an operator and can be blocked or can put your transactional sender at risk. Keep them on separate senders and templates. Our marketing and transactional pages show typical setups.

The rules you need to know

How to get opt-ins

A good list is built slowly and on purpose. Buying lists is illegal in many places and, even where it is not, it produces complaints that damage your sender reputation. These are the opt-in methods that hold up.

• Checkout checkbox. Unticked by default, with plain wording that says what you will send and how often.
• Sign-up form. A phone field with a short consent statement and a link to your privacy policy.
• Keyword opt-in. Customers text a word to a number, usually in store or from an ad.
• QR code. In stores, on packaging or at events, leading to a consent page.
• Existing customers. Only where the local rules allow it and the original sign-up covered texts; otherwise ask again.

Store the date, time, source and exact wording for every opt-in. If a regulator or an operator asks, that record is your defence.

SMS or another channel?

SMS is the safest base because it reaches everyone. On top of it, you can add WhatsApp for customers who chat there and RCS for branded cards on supported phones. A common pattern is to send the richer message first and fall back to SMS automatically.

What a good SMS marketing message looks like

1. Start with your brand. Make the sender obvious in the first words. "Telnxo: ..." works even if the sender ID is not recognised.
2. Give one reason to act. A single offer, a deadline or a benefit. Two offers in one message halve the response.
3. Add one clear action. A short link or a keyword to reply. Use your own short domain; shared shorteners are often flagged.
4. Keep it within one segment. Aim for 160 characters, or 70 if you use non-Latin scripts. Check drafts with the segment calculator.
5. End with the opt-out. "Reply STOP to opt out" or the local equivalent, as the law requires.

Timing, frequency and segmentation

• Send during permitted daytime hours in the recipient's time zone, not yours.
• Start with two to four messages a month and adjust by looking at opt-outs.
• Segment by what people bought or browsed, by location and by how recently they engaged.
• Welcome new subscribers at once, so the first message they receive is the one they expect.
• Use a holdout group that gets no message, so you can see the true lift.
• Avoid public holidays unless the offer is about the holiday.

How to measure SMS marketing

SMS cannot report whether a message was opened, so beware of platforms that promise open rates. Use delivery receipts through webhooks and the report in analytics for the numbers that are real. The cost calculator helps you plan spend against expected return.

SMS marketing examples by industry

• Retail and e-commerce. Back-in-stock alerts, flash sales for loyalty members and cart reminders. See e-commerce.
• Education. Admission deadlines, webinar reminders and result announcements. See education.
• Travel. Fare alerts, check-in reminders and gate changes. See travel.
• Healthcare. Appointment reminders and vaccination recalls, without sensitive details in the text. See healthcare.
• Financial services. Product updates sent only to consenting customers, kept apart from alerts. See fintech.

Sending a campaign through the API

For large lists, send through the API with a template and per-recipient variables. This illustrative request queues a campaign to a segment; field names are documented in the API reference.

{
  "channel": "sms",
  "sender": "TELNXO",
  "template": "autumn_offer",
  "category": "promotional",
  "audience": { "segment": "loyalty-members" },
  "variables": { "code": "SAVE20", "link": "example.com/s1" },
  "schedule": "2026-11-02T10:30:00+05:30",
  "respect_quiet_hours": true
}

Getting started

Start small. Register your sender and templates, send a welcome message to a consented list, and send your first promotion to a segment of a few thousand rather than the whole list. Read the delivery report the same day. Then repeat with the changes that the numbers suggest. Teams that begin with one send a week and a clean list outperform teams that blast everyone once a month. Our SMS product supports this from a dashboard or an API, and the DLT checklist covers India.

The best SMS marketing feels like a useful note from someone you chose to hear from.