How SMS works on Instant

How does SMS work on Instant?

SMS on Instant is billed the same way as email: your plan includes a monthly allotment based on send volume, and anything beyond that allotment is billed as overage. The only difference is that SMS usage is measured in credits rather than individual messages.

SMS is not a separate channel you need to design or manage. It works inside the flows and campaigns you already run, with Instant handling timing, targeting, and (in flows) the content itself.

How can I enable SMS?

To enable SMS, reach out to your CSM and they will be happy to support.

Before you can send, your business must complete a one-time verification process. Mobile carriers require proof that a business is legitimate before it can send commercial SMS. For Australian sending, you complete this in the SMS page under Configuration by submitting proof of business registration (such as an ABN extract) and proof of business addretss (such as a utility bill). Verification is typically processed within 48 hours. For US sending, your CSM will collect your business registration details and proof of SMS opt-in consent, and complete the process for you.

Note: verification is based on where your recipients are, not where your business is located. If you want to send to both Australian and US numbers, you need to complete both verifications.

Who is eligible to send SMS?

Any verified business can send SMS, with one exception: brands in carrier-restricted content categories. These restrictions apply in every region Instant supports — they are enforced by mobile carriers and messaging providers, and no amount of recipient consent overrides them.

The industry standard for restricted content is the SHAFT framework, which prohibits or restricts SMS relating to:

Sex — adult content, dating services, sexually suggestive content Hate — always prohibited, no exceptions Alcohol — permitted in the US only with age-gating (21+) in place Firearms — weapons, ammunition, and accessories Tobacco — including vapes, e-cigarettes, and smoking accessories

Carriers also restrict adjacent categories such as cannabis, CBD, gambling, payday loans, and debt collection. Brands in these categories may fail carrier registration or have their messages filtered, even when recipients have opted in.

Enforcement differs slightly by region. In the US, these rules come from the CTIA’s messaging principles and are checked during carrier registration. In Australia, gambling, firearms, and cannabis-related content is strictly prohibited at the carrier level, and the Spam Act additionally requires consent, sender identification, and a working unsubscribe in every message. Instant handles identification and unsubscribe automatically: every SMS includes your brand prefix and an auto-appended “Reply STOP to unsubscribe” line.

If you’re unsure whether your products fall into a restricted category, ask your CSM before starting verification.

Finally, Instant only sends SMS to shoppers who have given explicit SMS consent. SMS consent is separate from email consent, and unsubscribes sync both ways with Klaviyo if you have an integration.

What regions can I send SMS in?

SMS is currently available in Australia and the US.

What is a credit?

Text messages are transmitted in segments. A single SMS of up to 160 standard (GSM) characters is one segment; longer messages are split into multiple segments.

Each segment consumes credits based on where it’s sent:

United States: 1 credit Australia: 4 credits

Because usage is normalized into credits, SMS plan tiers are global — one credit allotment covers sending to any supported country. Note that pricing follows the recipient: a US brand sending to an Australian number is charged at the Australian rate.

Every SMS sent from a flow is kept within a single segment, so flow sends always cost a predictable one segment’s worth of credits.

Plan tiers

Your SMS plan is a monthly subscription that includes a set number of credits. Choose the tier that matches your typical monthly send volume — and if you need more than 3.5M credits per month, contact us for custom pricing.

What happens if I go over my included credits?

Your messages keep sending — nothing is paused or blocked. Credits consumed beyond your plan’s allotment are billed at your tier’s per-credit overage rate on your next invoice. If you’re regularly incurring overages, moving up a tier is almost always cheaper. Email notifications are delivered to brands when 70%, 90%, and 100% of credits are consumed to give plenty of advance notice.

Tracking your usage

Your credit consumption is metered in real time and visible in your Instant dashboard alongside your email usage, so you can always see where you stand for the current billing period.

How does SMS work in flows?

SMS is available inside your Abandoned Cart and Abandoned Checkout flows. There is nothing to build or write — enable SMS on a flow and Instant handles the rest.

  • Instant sends one SMS per enrollment, inserted at the highest-impact touchpoint of the flow. All other touchpoints send email as normal.
  • If a shopper has no SMS consent, no phone number, or a number in an unsupported region, Instant falls back to email — no shopper is skipped.
  • Each message is AI-generated per shopper, based on what they viewed, their cart, and your brand’s tone. If a coupon is configured on that touchpoint, it carries through to the SMS automatically.
  • If the shopper converts or unsubscribes before the SMS touchpoint, the SMS is skipped.
  • Every flow SMS stays within one segment, so the cost is predictable on every send.

Once live, your flow dashboard shows a full breakdown by channel: revenue split between email and SMS, sends, clicks, and deliverability, plus a per-message activity log where you can preview the exact SMS each shopper received.

How does SMS work in campaigns?

SMS is a step type inside multi-step campaigns. You can mix SMS and email steps in any combination, or send a standalone SMS-only campaign.

  • You write the content. Unlike flows, campaign SMS is written by you: 120 characters including your brand prefix, with a live character count in the editor. A first-name variable with a fallback value is supported.
  • One link, always. Every SMS includes exactly one link (your store URL by default). SMS attribution is click-based, so the link is required. The unsubscribe line is appended automatically and doesn’t count toward your character limit.
  • One segment for the whole campaign. You pick a single audience segment, and Instant works out who receives each step: email-only subscribers get email steps, SMS subscribers get SMS steps, and shoppers subscribed to both get both.
  • Each step has its own send time, in your store’s local time zone.

SMS results — sends, clicks, attribution, and revenue — appear in your campaign analytics alongside email, so you can compare both channels in one place.