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SMS: Link shortening

By default, when you enable SMS, we automatically shorten links in your message body. This page explains how link shortening works.

How it works

By default, 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.

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!

We recycle links after 90 days

We do not reuse link paths across workspaces; your shortened links are unique to your workspace. But, because we reuse link paths after 90 days, someone who clicks a link in a message that’s older than 90 days could end up on a URL you did not originally intend.

It’s rare that people engage with messages older than 90 days, but you should always require a login if you send links to sensitive information so that you don’t expose personal information to the wrong users—even if they click a link in an old message.

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!

// 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

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.