How to Combine Klaviyo Email and SMS into a Single Flow

Email and SMS are stronger together than apart. Email carries the detail—images, product blocks, longer copy—while SMS lands an urgent, time-sensitive nudge straight on the lock screen. Klaviyo lets you run both from a single flow, which is exactly what you want: one coordinated sequence rather than two disconnected ones that accidentally hit the same person twice. The skill is not adding SMS—it is structuring the flow so every subscriber gets the right message on the right channel, once.

The golden rule: one trigger, consent decides the rest

A Klaviyo flow has a single entry trigger (placed an order, abandoned a cart, joined a list). You do not build a separate SMS flow and an email flow for the same event—you build one and add both channels inside it. The crucial part is consent: Klaviyo will only send an SMS to a profile that has SMS consent, and it automatically skips anyone who does not. Email consent and SMS consent are separate things, so your flow has to account for three kinds of people —email only, SMS only, and both—without spamming the last group.

Two ways to structure a combined flow

There are two clean patterns, plus a popular hybrid. Pick based on how much control you want over who gets what.

• Conditional split on SMS consent. Add a conditional split that checks whether the profile is consented to SMS. SMS-consented subscribers go down a path that uses text (or text plus email); everyone else goes down an email-only path. This gives you the most deliberate control and prevents an SMS landing seconds after an identical email.
• Single path, let Klaviyo skip. Drop SMS messages inline in one sequence alongside the emails. Because Klaviyo will not text a profile without SMS consent, non-consented people simply skip the SMS steps automatically. Simpler to build, but you have less say over timing overlap.
• Email first, SMS follow-up. A favourite for conversion: send the email, add a time delay, then send an SMS to people who have not yet acted. Instead of duplicating the message, SMS becomes the gentle second tap for those who did not open or click.

The mistake to avoid is placing an email and an SMS back to back with no split and no delay—someone consented to both then gets the same message twice in the same minute. Use splits or delays so the two channels complement each other rather than collide.

Building it, step by step

The exact screens shift as Klaviyo updates its interface, so treat this as the shape of the job and confirm each step in your account:

• 1. Enable SMS. Set up SMS in Klaviyo and provision a sending number for your country. Without this, SMS blocks have nowhere to send from.
• 2. Collect SMS consent properly. Add an SMS opt-in to your signup forms and checkout—separate from the email opt-in. This is the step that determines who is even eligible for the SMS branch later.
• 3. Open the flow and keep one trigger. Build (or edit) the flow for your event—welcome, abandoned cart, post-purchase—with a single entry point.
• 4. Add the conditional split. Insert a split on SMS consent so consented profiles take the text-enabled path and the rest stay on email.
• 5. Add SMS messages and time delays. Place SMS blocks where they earn their keep, with delays between channels so messages are spaced, not stacked.
• 6. Set quiet hours and smart sending. Use quiet hours so texts never arrive overnight, and smart sending to avoid over-messaging someone who has heard from you recently.
• 7. Test, then turn live. Run a profile through both paths—email only and SMS-consented—before you switch the flow from draft to live.

Get the Australian compliance right

SMS rules are stricter than email—do not assume one consent covers both. Under Australia's Spam Act 2003, marketing texts require consent (the ACMA recommends express, unambiguous opt-in), the message must clearly identify your business, and it must include a working unsubscribe that stays functional for at least 30 days and is actioned within 5 business days. Email consent does not imply SMS consent—collect SMS opt-in separately, which is precisely why the consent split in your flow matters. The ACMA enforces this, so treat it as a setup requirement, not a nicety. This is general information, not legal advice—confirm your obligations for your situation.

Best practices that keep it working

• Use each channel for what it is good at. Email for detail and storytelling; SMS for short, urgent, time-bound prompts—an order update, a sale closing, a cart about to expire.
• Reserve SMS for high-value moments. It is more intrusive and costs per send, so texting too often burns goodwill and budget. Fewer, better texts win.
• Mind the timing. Delays and quiet hours stop the two channels from arriving on top of each other or at antisocial times.
• Let the data steer the channel. Lean on engagement and channel preference so the people who respond to texts get more of them, and the people who do not are left to email.

If you are still deciding whether Klaviyo is the right platform for your store in the first place, our comparison of Klaviyo vs Mailchimp for Shopify covers where each one fits. And for the authoritative, up-to-date steps, Klaviyo's own guide on using email and SMS together is the reference to check as the interface evolves.

Takeaway: Build one flow with a single trigger, collect SMS consent separately, and use a conditional split (or an email-first, SMS-follow-up pattern) so email and SMS work together instead of doubling up. Add delays, quiet hours, and smart sending, get the Spam Act basics right, and reserve SMS for the moments that genuinely warrant a buzz in someone's pocket.

Want this set up cleanly against your store data—flows, consent, and segments syncing correctly? Our Shopify integration services cover the connections that keep your marketing automation in sync.