SMS

In digital marketing, SMS (Short Message Service) is a text messaging channel that allows businesses to send short, text-based messages directly to customers’ mobile phones. SMS messages are delivered through cellular networks and appear in the native messaging app on any mobile device, making it one of the most direct and immediate ways to reach your audience.

For example, a restaurant might send an SMS to confirm a reservation, a retailer might alert customers to a flash sale, or a healthcare provider might send appointment reminders—all delivered as simple text messages that recipients can read instantly.

While SMS is primarily a mobile messaging channel rather than email, it’s increasingly relevant to email marketers as businesses adopt multi-channel communication strategies that combine email, SMS, and other channels to reach customers where they’re most responsive.

Why SMS matters for marketers

SMS offers unique advantages that make it a powerful complement to email marketing.

• Immediate delivery – SMS messages are typically delivered within seconds, making them ideal for time-sensitive communications.
• High open rates – SMS messages have open rates of 90% or higher, significantly outperforming email. Most people read text messages within minutes of receiving them.
• Direct reach – SMS goes straight to the recipient’s phone, bypassing spam filters, promotional tabs, and inbox clutter.
• Universal compatibility – Unlike app-based messaging or RCS, SMS works on every mobile phone, regardless of device type, carrier, or operating system.
• High engagement – The immediacy and personal nature of SMS drives strong engagement, particularly for transactional messages and time-sensitive offers.

How SMS differs from email

SMS and email serve different purposes and excel in different scenarios. Understanding when to use each channel helps you build a more effective marketing strategy.

SMS strengths

• Immediate, direct delivery to mobile devices
• Extremely high open and read rates
• Best for short, urgent, or time-sensitive messages
• Works on all mobile devices
• Highly personal channel

SMS limitations

• Character limit (160 characters per message)
• Text-only format (or limited multimedia via MMS)
• Higher cost per message than email
• Requires explicit consent and careful compliance
• Limited space for detailed information or storytelling

Email strengths

• Rich formatting with images, videos, and design
• Unlimited length for detailed content
• Lower cost per message
• Better for newsletters, long-form content, and brand storytelling
• Easier to segment and personalise at scale

Many businesses use SMS and email together, choosing the right channel based on message type, urgency, and customer preference.

Common use cases for SMS

SMS excels in situations where immediacy, simplicity, and direct reach matter most.

Appointment reminders and confirmations

Healthcare providers, salons, and service-based businesses send SMS reminders to reduce no-shows and confirm bookings.

Example: “Reminder: Your dental appointment is tomorrow at 2pm. Reply C to confirm or R to reschedule.”

Order and delivery updates

E-commerce businesses use SMS to notify customers when orders ship, provide tracking links, and confirm delivery.

Example: “Your order has shipped! Track it here: [link]”

Time-sensitive promotions

Flash sales, limited-time offers, and event announcements benefit from SMS’s immediacy and high open rates.

Example: “Flash sale! 24 hours only—20% off everything. Shop now: [link]”

Two-factor authentication and security alerts

Banks, fintech companies, and online platforms send SMS codes for login verification and fraud alerts.

Example: “Your verification code is 482951. Do not share this code with anyone.”

Customer support and updates

Businesses use SMS for service updates, outage notifications, and quick customer support interactions.

Example: “We’re experiencing higher than normal call volumes. Estimated wait time: 15 minutes. We’ll call you back when it’s your turn.”

Event reminders and tickets

Event organisers send SMS reminders, ticket confirmations, and last-minute updates to attendees.

Example: “Your concert is tonight at 7pm. Doors open at 6pm. Show this message at the gate for entry.”

SMS marketing regulations in Canada

In Canada, SMS marketing is governed by CASL (Canada’s Anti-Spam Legislation), one of the world’s strictest anti-spam laws. CASL applies to all commercial electronic messages, including SMS.

Key CASL requirements for SMS

• Express consent is required – You must have clear, documented consent before sending commercial SMS messages. Consent must be explicit—pre-checked boxes, assumed consent, or purchased lists are not compliant.
• Implied consent has limits – You may have implied consent in specific situations, such as an existing business relationship, but this consent is time-limited and doesn’t cover all types of messages.
• Identify yourself clearly – Every SMS must clearly identify your business or organisation.
• Include unsubscribe mechanism – Recipients must be able to easily opt out of future messages. This is typically done by including instructions like “Reply STOP to unsubscribe.”
• Honour opt-outs immediately – Unsubscribe requests must be processed promptly, and you cannot send further commercial messages once someone opts out.
• Keep consent records – You must document when and how you obtained consent, as well as opt-out requests.

Violating CASL can result in significant penalties—up to $10 million for businesses. Compliance isn’t optional, and it protects both your recipients and your sender reputation.

What counts as a commercial message

Under CASL, a commercial electronic message (CEM) is any message that encourages participation in commercial activity, such as:

• Promotional offers or sales
• Product announcements
• Marketing campaigns

Messages that are purely transactional or informational—like appointment confirmations, order updates, or account notifications—are generally exempt from CASL’s consent requirements, though best practices still apply.

How to build a compliant SMS list

Growing an SMS list requires careful attention to consent and compliance.

• Use clear opt-in forms – When collecting phone numbers, clearly state that the person is agreeing to receive SMS messages from your business. Explain what types of messages they’ll receive and how often.
• Consider double opt-in – After someone subscribes, send a confirmation message asking them to reply YES or CONFIRM to verify their consent. This adds an extra layer of protection and ensures the number is valid.
• Collect consent at relevant touchpoints – Add SMS opt-in options to your website, checkout process, email signup forms, or in-store interactions. Make sure consent is always explicit and documented.
• Never buy or rent SMS lists – Purchased lists violate CASL and result in poor engagement, spam complaints, and potential legal consequences.
• Make unsubscribing easy – Include clear opt-out instructions in every commercial SMS, such as “Reply STOP to unsubscribe.” Honour these requests immediately.

SMS best practices

To get the most from SMS marketing while respecting your audience, follow these guidelines.

• Keep messages short and clear – With only 160 characters, every word counts. Get to the point quickly and include a clear call to action.
• Personalise when possible – Use the recipient’s name or reference their specific situation (like an upcoming appointment or recent order) to make messages feel relevant.
• Time messages appropriately – Avoid sending SMS late at night or early in the morning. Respect your audience’s time and send messages during reasonable hours (typically 9am–8pm).
• Include your business name – Recipients should immediately know who the message is from. Start with your business name or include it early in the message.
• Provide value – Every SMS should offer something useful—whether it’s important information, a valuable offer, or a helpful reminder. Don’t waste your audience’s time.
• Respect frequency preferences – SMS feels more intrusive than email. Be conservative with send frequency and let subscribers choose how often they hear from you.
• Use a recognisable sender ID – If your platform supports it, use a branded sender name or shortcode instead of a random phone number.
• Test before sending – Always test your messages on different devices to ensure formatting, links, and character count work correctly.

MMS: Adding multimedia to SMS

MMS (Multimedia Messaging Service) is an extension of SMS that allows you to send images, videos, GIFs, and longer messages (up to 1,600 characters).

MMS can make messages more engaging and visually appealing, but it comes with trade-offs:

• Higher cost per message than SMS
• Not universally supported on all devices or carriers
• Larger file sizes can cause delivery issues
• Messages may fall back to SMS on unsupported devices, losing the multimedia content

Use MMS when visual content adds clear value—like showcasing a product, sharing a coupon, or sending event photos. For simple, text-based messages, stick with SMS.

SMS metrics and performance tracking

Like email, SMS marketing relies on key metrics to measure success.

• Delivery rate – The percentage of messages successfully delivered to recipients. High bounce rates may indicate invalid numbers or carrier issues.
• Open rate – While difficult to track precisely for SMS, open rates are generally assumed to be very high (90%+) since most people read texts immediately.
• Click-through rate (CTR) – If your message includes a link, CTR measures how many recipients clicked it.
• Conversion rate – The percentage of recipients who completed the desired action, such as making a purchase, confirming an appointment, or RSVPing to an event.
• Opt-out rate – The percentage of recipients who unsubscribe after receiving a message. A high opt-out rate signals irrelevant content, poor timing, or excessive frequency.

Monitor these metrics to understand what’s working and where you can improve.

SMS and multi-channel marketing

SMS works best as part of a broader communication strategy that includes email and other channels.

• Use email for – Newsletters, long-form content, detailed product information, and campaigns requiring rich visuals or storytelling.
• Use SMS for – Time-sensitive alerts, appointment reminders, order updates, and short, urgent promotions.
• Coordinate across channels – For example, send an email announcing a sale, then follow up with an SMS reminder on the last day. Or use email for onboarding content and SMS for appointment confirmations.

By combining channels based on message type and customer preference, you create a seamless, effective customer experience.

Getting started with SMS marketing

To launch SMS marketing, you’ll need an SMS platform or provider that supports business messaging.

Many email marketing platforms now offer SMS capabilities, making it easy to manage both channels from one place. Look for features like:

• CASL-compliant opt-in and opt-out management
• Contact segmentation and personalisation
• Scheduling and automation
• Link tracking and analytics
• Integration with your existing email and CRM tools

Start small—begin with transactional messages like appointment reminders or order confirmations, then expand to promotional campaigns as you learn what resonates with your audience.

Key takeaway

SMS (Short Message Service) is a direct, immediate messaging channel that delivers text-based messages to customers’ mobile phones. With high open rates and universal reach, SMS is a powerful complement to email marketing for time-sensitive communications, transactional updates, and urgent promotions. In Canada, SMS marketing requires strict compliance with CASL, including explicit consent and clear opt-out mechanisms. When used thoughtfully as part of a multi-channel strategy, SMS helps businesses reach customers where they are and drive meaningful engagement.