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SMS: Link shortening

When you enable SMS and turn on the setting Shorten links, we shorten links in your SMS and Whatsapp message bodies. This page explains how link shortening works.

How it works

In Workspace settings > SMS, you’ll see a toggle for Shorten links. When this is enabled, we automatically shorten links in your SMS/MMS messages. Shortened links use the format https://a.cust.io/lnk.abc123 (or https://e.cust.io/lnk.abc123 if you’re in our EU region) and consume between 28 and 38 characters (out of 160):

• 8 for the https:// prefix.
• 9 for the domain (a.cust.io or e.cust.io).
• 11-16 characters for the path (the slash and random characters /lnk.abc123). We start with a 10 character path and increase the length until we find a path that isn’t in use.
• Shortened links expire after 90 days.

When someone clicks a shortened link, the link directs them to Customer.io, where we’ll resolve the link and then send your audience to the ultimate destination.

Shortened links are especially helpful if you want to track when people click links in your messages. Normally, tracked links won’t reliably fit inside a 160 character SMS message; shortened links fix that!

Track link-clicks in your messages

To track links in your SMS/MMS messages, you’ll use liquidA syntax that supports variables, letting you personalize messages for your audience. For example, if you want to reference a person’s first name, you might use the variable {{customer.first_name}}. in the format {% cio_link url:"https://example.url" %}. While we’ll shorten other links, tracked links let us track the links that people engage with. You can use tracked links to track engagement or trigger subsequent messages. You can’t do this unless you use the {% cio_link %} tag!

In your message preview, you’ll see example links that end in abc123 to help you see your links in context and check your character count. These links don’t work. We don’t generate the shortened URL until send time.

// tracked link example
{% cio_link url:"https://example.url" %}

// un-shortened link
http://e.customeriomail.com/e/c/eyJlIjo5Nzk3NSwiZW1haWxfaWQiOiJleGFtcGxlIiwiaHJlZiI6Imh0dHBzOi8vZXhhbXBsZS51cmwiLCJsaW5rX2lkIjo4LCJ0IjoxNzQxNjI3ODM0fQ/fff492f75bd0c23298bd5ff01a9b1c0edd93eac33d0c47462a82d6a8c65dcc5a

// shortened link
https://a.cust.io/lnk.abc123

Shortened links expire after 90 days

Short link paths expire after 90 days. Your workspace can reuse paths after they expire, but immediate reuse is unlikely given the large number of possible combinations.

While it’s unlikely that an expired path gets reused, or that users engage with messages older than 90 days, you should require a login if you send links to sensitive information. This ensures that you don’t expose personal information to users who click old links.

Disable link shortening

If you don’t want to shorten links, you can disable link shortening. But if you don’t shorten links, keep in mind that you probably won’t want to track links in your messages because tracked links consume significant space in your messages.

1. Go to your > workspace settings > SMS.

2. Disable Link shortening.