SMS Marketing and Short URLs - Strategies to Maximize the 160-Character Limit

While email open rates are stagnating, SMS stands out with notably high open rates, and messages are often read soon after they arrive. In an era where push notification opt-in rates are declining and emails get buried in spam folders, SMS is being reevaluated as a channel that reliably delivers messages.

However, SMS has one decisive constraint: a 160-character limit per message (70 characters for Japanese). Fitting both a compelling message and a URL within this limit makes short URLs indispensable.

Let us compare an actual URL with its shortened version.

If the original URL is `https://www.example.com/campaigns/summer-sale-2025?utm_source=sms&utm_medium=text&utm_campaign=july` (99 characters), the shortened version becomes `https://exm.pl/s7k` (18 characters). That is a savings of 81 characters.

With the 160-character SMS limit, the original URL alone would consume more than half the message. A shortened URL frees up the remaining space for a compelling call to action. Whether you can include a CTA like "30% OFF today only" is a difference that can affect conversions.

The CTR of short URLs in SMS tends to be well above that of links in email. There are ways to push this even higher.

First, use branded links. `shop.brand.com/sale` inspires more trust than `bit.ly/xyz` and is more likely to lead to a higher CTR. Second, consider link placement. Click rates can vary with placement, so compare mid-message and end-of-message links to see which works better. Third, personalize. Setting the link destination based on the recipient's name or purchase history is expected to raise CTR.

The most frustrating barrier in SMS marketing is carrier-level URL filtering. As a spam countermeasure, carriers may automatically block or delay SMS messages containing shortened URLs. Free URL shortening services are especially vulnerable because they are frequently abused by spammers.

Here are the countermeasures.

• Use branded links on your own domain (avoid shared-domain short URLs)
• Pre-register your sender number with carriers (in the US, A2P 10DLC registration)
• Manage sending frequency carefully and avoid sudden spikes in volume
• Always include an opt-out (unsubscribe) mechanism
• Ensure the destination domain supports SSL

In the United States, the Telephone Consumer Protection Act (TCPA) applies to SMS marketing. Sending marketing messages without prior consent is generally a legal violation, making opt-in management mandatory.

RCS (Rich Communication Services) is gaining traction as the successor to SMS. With Google Messages and Apple's iMessage supporting RCS, it is now possible to send rich media (images, carousels, buttons) that traditional SMS could not handle.

RCS significantly relaxes character limits and supports link previews (OGP). This means the "character savings" role of short URLs diminishes. However, the value of click analytics and branded links for trust remains unchanged in an RCS environment. In fact, placing branded links within RCS rich cards enables a more polished user experience.

That said, RCS adoption is not yet at 100%, and messages to unsupported devices fall back to traditional SMS. For now, designing for both SMS and RCS is necessary.

In SMS marketing, short URLs are more than a character-saving tool - they serve as the foundation for CTR optimization, carrier filtering avoidance, and campaign improvement through click analytics. Even as RCS adoption grows, the value of branded links and analytics capabilities endures. If you are leveraging SMS, short URL strategy should be built into your plan from the start.