SMS marketing for small business: rules, costs and a simple setup

SMS marketing means sending short promotional or reminder texts to customers who have agreed to receive them. It still works because almost every phone can receive a text, with no app needed. To do it safely you need three things: clear consent, a registered sender where your country requires one, and an SMS provider that sends the messages for you.

This guide explains each part in plain words, with extra detail for the US and India, where the rules are strictest.

When is SMS the right channel?

SMS is the right channel when reach matters more than rich content. Every mobile phone gets texts, even without data or apps.

Use SMS for:

• Time-sensitive reminders: appointments, deliveries, payment due dates.
• One-time passwords and alerts.
• Short offers to customers who don't use WhatsApp, or who prefer texts.
• A backup when a WhatsApp message fails.

SMS is weaker for long messages, images, and two-way chats. Most standard texts are limited to 160 characters (fewer if you use emoji or non-Latin scripts), and each reply costs your customer a normal text. If your customers live on WhatsApp, read WhatsApp vs SMS vs email before choosing.

Do you need permission to send marketing texts?

Yes. In most countries you need someone's clear permission before you send them marketing texts, and you must let them stop easily.

In the US, the Telephone Consumer Protection Act (TCPA) requires prior express written consent for marketing texts. In practice that means the person actively agreed (no pre-ticked boxes), the sign-up said they'd get texts from your business, and roughly how often. Every message should explain how to opt out, usually "Reply STOP to unsubscribe". The FCC's consumer guide says people may revoke consent "in any reasonable manner", so treat "stop texting me" the same as STOP.

In the EU and UK, GDPR and electronic marketing rules also require consent for most marketing texts to individuals.

In India, commercial SMS is governed by TRAI's rules on commercial communication, and customer preferences are respected through the Do Not Disturb registry. See the registration section below.

Keep a record of when and how each person agreed. If a complaint ever comes up, that record is your proof.

This is general information, not legal advice. If SMS is a big part of your marketing, check the rules for each country you send to.

What is 10DLC and do you need it? (US)

10DLC stands for "10-digit long code", which is an ordinary US phone number used for business texting. US carriers require businesses that send application-to-person (A2P) texts from these numbers to register their brand and their type of messaging through their SMS provider.

Unregistered traffic is heavily filtered or blocked, even if your consent is perfect. Registration is done in your SMS provider's dashboard (Twilio, Telnyx, Plivo and others all offer it), usually takes a few days, and involves a small fee set by the carriers and your provider.

What is DLT registration? (India)

DLT is the registration system that Indian telecom operators run under TRAI rules. Before any business can send commercial SMS in India, it must register three things on a DLT portal:

1. The entity: your business.
2. Headers: the sender ID people see, such as OMNIIN.
3. Templates: the exact text of each message, with variables marked.

If the header or template in a message doesn't match what's registered, the operator drops it. Indian SMS providers such as MSG91 and Fast2SMS ask for your DLT details when you set them up. TRAI's advice to senders page is the official starting point.

How much does SMS marketing cost?

You pay your SMS provider per message segment sent. Prices vary a lot by country, so check your provider's pricing page for the countries you send to. As a rough guide, texts within India are usually much cheaper per message than texts to the US or UK.

Three things change your bill:

Cost driver	What to know
Message length	Over 160 plain characters (or 70 with emoji/Unicode) splits into several billed segments
Destination country	Each country has its own per-message rate
Registration fees	10DLC (US) and DLT (India) have one-time or recurring fees

Tip: read your message aloud and cut every word you can. A 150-character text costs half as much as a 170-character one.

Example SMS messages that work

Keep them short, name your business, and give one clear action.

Appointment reminder:

Sunrise Dental: Hi Meera, reminder of your check-up tomorrow at 10:30. Reply C to confirm or call 020-5555-0100 to change.

Offer to opted-in customers:

Bloom Florist: 15% off all bouquets this weekend with code SPRING15. Shop: bloom.example/offer Reply STOP to opt out.

Win-back:

FitHub: We miss you, Karan! Come back this month and your first week is free. Book: fithub.example/back STOP to opt out

How to run SMS campaigns with your own provider

The simplest setup is to keep your SMS provider for sending and use a campaign tool for audiences, scheduling and tracking.

1. Pick a provider that covers your countries and handles registration (10DLC, DLT or local sender IDs).
2. Complete registration in the provider's dashboard.
3. Import only opted-in contacts, with phone numbers in international format (for example +14155552671).
4. Send a test to your own phone.
5. Start small, check delivery, then send to the rest.
6. Watch opt-outs and failures, and remove numbers that repeatedly fail.

In Omni, you connect your own SMS provider under Campaigns → SMS gateways. It supports 15 providers, including Twilio, Vonage, MessageBird, Plivo, Telnyx, Infobip, ClickSend, Amazon SNS, MSG91 and Fast2SMS, plus several Bangladesh gateways (full list and credentials). Your provider bills you for the texts directly, so there's no markup on messages.

When you create an SMS campaign, you choose a segment, tag or uploaded list, preview the exact audience, send a test, and schedule it. Omni skips any contact whose SMS opt-in is off, spreads sending out instead of firing everything at once, and shows each recipient's status. SMS campaigns are available from the Starter plan (2,500 texts a month), and the Free plan doesn't include SMS; see pricing.

One thing to know: SMS replies (including STOP) go to your provider, not the Omni inbox. Most major providers handle STOP automatically. Check that yours does, and switch off SMS opt-in for anyone who unsubscribes.

Common SMS marketing mistakes

• Buying number lists. It breaks consent laws and gets your sender blocked.
• No business name. People ignore or report texts from unknown senders.
• Sending at night. Many US state rules and good manners say to avoid early mornings and late evenings.
• Links from free shorteners. Carriers often filter them. Use your own domain.
• Too many messages. Two or three a month is plenty for most businesses.

Sources

• TRAI: Advice to senders of commercial communication
• US FCC: Telephone Consumer Protection Act consumer guide
• Infobip: India DLT registration