Definition
SMS (Short Message Service) marketing involves sending promotional or transactional text messages to subscribers who have opted in to receive them. With open rates of 90–98% within three minutes of delivery, SMS is the highest-engagement marketing channel — but its immediacy makes it more intrusive than email.
SMS and email marketing are often paired as complementary channels. Email handles detailed content, long-form storytelling, and lower-frequency engagement. SMS handles urgent, time-sensitive, and high-impact messages — flash sales, shipping updates, appointment reminders, and two-factor authentication. Brands that coordinate both channels see higher overall engagement and conversion rates.
SMS vs Email Marketing
| Factor | SMS Marketing | Email Marketing |
|---|---|---|
| Open rate | 90–98% (within 3 min) | 20–30% (within 24 hr) |
| Character limit | 160 characters | Unlimited |
| Content depth | Short, direct | Detailed, rich media |
| Cost per send | Higher | Lower |
| Regulatory consent | Explicit opt-in required | Opt-in varies by jurisdiction |
| Best for | Urgent, time-sensitive | Educational, promotional, nurture |
Best Practices
- Obtain explicit opt-in consent for SMS — it is legally required in most jurisdictions
- Keep messages under 160 characters for single-segment delivery
- Use SMS for time-sensitive, high-value communications only
- Coordinate SMS timing with email campaigns to avoid over-messaging
- Include a clear opt-out mechanism (e.g., "Reply STOP to unsubscribe")
- Track SMS click-through rates separately from email engagement
- Respect quiet hours — avoid sending SMS late at night or early morning
Related Glossary Terms
Email & SMS Strategy
An email and SMS strategy coordinates both channels to deliver a unified cross-channel communication experience, using each channel's strengths at the right point in the customer journey.
Email vs SMS
Email vs SMS compares digital email with text message marketing across cost, engagement, timing, content, and compliance to help marketers choose the right channel for each communication.
Frequently Asked Questions
SMS has higher open and response rates, but email generates more revenue per campaign due to its depth and lower cost. The most effective approach is using each channel for what it does best — SMS for urgency and immediacy, email for storytelling and nurture.
In the US, SMS marketing requires prior express consent under the Telephone Consumer Protection Act (TCPA). In the EU/UK, explicit opt-in consent is required under GDPR and ePrivacy. Canada's CASL requires express consent. Always maintain clear consent records and provide easy opt-out mechanisms.