Short Message Service (SMS): Text messaging for mobile devices

How SMS Enables Mobile Communication

Take a concrete case: A local services business relies on regular updates and confirmations to its customers, sending out about 6,000 text messages every month. No matter what brand of mobile device the recipient uses, SMS reaches almost everyone, as it works on any phone that supports basic messaging. Unlike data-driven messaging apps, SMS does not require an internet connection, which means recipients will likely get time-sensitive information even in areas with weak or no Wi-Fi or mobile data. This reliability has made SMS central to day-to-day mobile communication, especially for appointment reminders, security codes, and quick personal messages.

While email and app-based messaging offer rich content and features, SMS stands out for simplicity and speed. Few alternatives can match its near-instant delivery and vast compatibility. Businesses making use of SMS can be assured that critical messages—such as same-day booking reminders or service notifications—will typically reach people within seconds, regardless of handset sophistication or network access.

• Messages are delivered instantly, even on basic phones
• Recipients do not need mobile data or Wi-Fi to receive texts
• Useful for urgent alerts or confirmations
• High open rates compared to email or app notifications
• Works reliably across different networks and geographies
• No need for users to install or update separate apps

Business Uses of SMS Messaging

Look at the numbers: a Galway-based food delivery service sends order confirmations and time updates via text to 7,200 customers each month. This steady stream of SMS alerts improves customer experience by setting clear expectations for delivery times. Customer feedback after six months showed missed or confused orders dropped by nearly 25%, directly boosting satisfaction and repeat business. On top of customer notifications, businesses use SMS to run time-limited promotions, issue appointment reminders, and communicate important updates with staff.

Short Message Service is prized for its immediacy and high open rates, making it a go-to for flash sales or urgent alerts. However, a key risk is overuse: frequent, irrelevant texts can lead customers to opt out. For internal communications, SMS is valued for reaching staff without the need for internet access, especially useful in sectors like logistics or healthcare where teams are often on the move.

• Order updates and delivery confirmations sent directly to customers’ mobiles
• Time-sensitive promotion alerts during quiet trading periods
• Appointment reminders to reduce no-shows
• Two-way feedback surveys after a service or purchase
• Emergency or urgent notifications for staff
• Internal coordination when staff are off-site or dispersed

Key Features and Character Limits of SMS

SMS messages are typically limited to 160 characters when using standard GSM encoding, which includes most European alphabets and symbols. If your message contains characters outside the standard set, such as emojis or certain non-Latin scripts, encoding switches to Unicode. This reduces your usable space to 70 characters per message. Understanding which encoding your content triggers is crucial, as exceeding character limits will split your message into multiple segments, potentially incurring extra costs or confusing recipients if the sequence is not maintained.

Message delivery is usually swift, but several factors can affect reliability. Network congestion, handset compatibility, or incorrect recipient numbers may cause a delay or complete failure. In practice, a company sending 8,400 messages a day (derived from the formula: 1200 x (3 + 4)) needs to factor in possible segmentation. For example, using Unicode characters could immediately double or triple the number of actual SMS parts, impacting both cost and customer experience.

• Standard SMS allows 160 characters; Unicode reduces this to 70
• Using emojis or non-Latin scripts often triggers Unicode encoding
• Messages longer than the limit are split and sent as multiple parts
• Each split part is billed as a separate message by most providers
• Delivery speed and reliability depend on recipient device and network
• Always preview messages to ensure intended format and character count
• Regularly check for message truncation if lists are dynamically generated

Differences Between SMS and Other Messaging Platforms

Run the maths on this: say a local retailer decides to communicate special offers to 8,000 customers using a classic text message approach. With SMS, all the messages are delivered straight to the users’ phones, regardless of the type or age of their device, because SMS works on any mobile without an internet connection. In contrast, if the retailer switched to app-based messaging, only customers who have the right app installed and notifications enabled would see the message, reducing effective reach. Moreover, app-based services can carry images, menus and buttons, but they introduce additional dependencies and may not be as immediate.

When it comes to cost, SMS pricing is typically based on volume, with a fixed charge for each message sent. This makes budgeting fairly predictable, but the cost can climb quickly with large lists. Messaging apps may appear “free,” but their engagement relies on users having the service active, and there could be hidden costs in setting up campaigns or integrating rich media elements. Due to these factors, user behaviour varies—SMS often sees higher open rates but a shorter message lifespan, while media-rich apps encourage longer engagement but cannot always guarantee timely attention.

A key tip: consider your audience’s habits before settling on a channel. SMS is unmatched for speed and reach, but multimedia or interactive content needs an app-based approach. Make the choice based on both the message and your customers’ preferred ways to engage.

Practical Example: Sending an SMS Notification

Here is a simple example: a local restaurant wants to notify its 5,400 loyalty club members about a last-minute weekend special. Using a messaging platform, the manager prepares a message inviting members in for a discounted meal. Each member’s mobile number is already in the system, making the process straightforward.

The manager logs in, creates a new campaign, and selects ‘SMS notification’. The message is composed, the recipients are confirmed, and a schedule is set for 10am on Friday. After confirming the text and reviewing the contact list, the system sends all 5,400 messages at once. Reports later show that over 90% were delivered within five minutes, with a good number redeemed at the restaurant that weekend.

• Check subscriber permissions and data privacy before uploading contacts
• Craft a clear, concise message that fits the standard SMS character limit
• Test the message with a small internal list to ensure formatting works
• Schedule delivery for times when recipients are likely to read texts
• Review delivery reports to track effectiveness and spot any sending issues