SMS isn’t just another channel — it’s your brand’s fastest route to attention. With 90% of texts read within 3 minutes and only 52% of consumers subscribing to 2–3 SMS lists, standing out isn’t easy — but it’s worth it.

That’s where Klaviyo SMS flows come in. When set up properly, they help you:

• Recover lost sales in real time

• Reward your best customers with VIP perks

• Re-engage lapsed buyers

• Trigger instant alerts for price drops, back-in-stock items, and more

In this guide, we’ll break down:

• What Klaviyo SMS flows are

• How to stay compliant and avoid opt-outs

• 9 essential SMS automations

• Ways to personalise, test, and optimise your flows

Let’s turn your SMS channel into a high-retention, high-revenue machine.

What Are Klaviyo SMS Flows?

Klaviyo SMS flows are automated text message sequences triggered by actions (e.g. checkout started), profile updates (e.g. birthday), or custom events (e.g. loyalty tier change). Built in Flow Builder, these automations allow brands to send timely, personalised SMS at every stage of the customer journey—from welcome to win-back.

SMS flows are a core part of Klaviyo's omnichannel capabilities and are used to:

• Recover abandoned carts

• Drive post-purchase engagement

• Boost customer lifetime value

• Reactivate lapsed customers

• Provide transactional updates (e.g., shipping, order confirmation)

Note: All SMS flows must respect consent. Use filters like ‘Has consented to receive SMS’ to stay compliant.

How Klaviyo SMS Flows Differ from Email-Only Automations

An SMS flow in Klaviyo is any automation that includes one or more SMS message blocks—but they can vary in format and logic:

• Standalone SMS Flows: e.g. a shipping update or order confirmation sent only via text

• Multichannel Flows: where SMS complements an email (e.g. reminder follows an abandoned cart email)

• Smart Conditional Flows: using logic like “Has consented to receive SMS” to ensure compliance and personalise the experience

Pro Tip: You can also add branching paths to send SMS to opted-in users and email to others—perfect for blending compliance with performance.

We cover smart SMS segmentation, consent filters, and flow personalisation in Klaviyo SMS Quiet Hours: Smart Way to Avoid Annoying Customers.

Consent & Compliance — SMS Setup That Builds Trust

Before sending SMS messages in Klaviyo, collecting explicit, documented consent is both legally required and a best practice. Regulations like TCPA (US), GDPR (EU), and CASL (Canada) impose strict messaging rules. Klaviyo provides tools for compliant opt-in, quiet hours, and unsubscribes.

How to Collect SMS Opt-In in Klaviyo

You can gather consent through:

• Klaviyo sign-up forms (popups, flyouts, embedded)

• Checkout opt-in checkboxes (integrated with platforms like Shopify, BigCommerce, and WooCommerce)

• Keyword reply campaigns (e.g., “Text JOIN to 12345”)

Klaviyo automatically stores opt-in metadata (timestamp, source, and method) on the user’s profile—vital for audits.

Use clear, compliant language (e.g., “Message and data rates may apply. Reply STOP to unsubscribe.”).

Consider double opt-in for international audiences where stricter consent laws apply (e.g. GDPR, CASL), especially if your opt-in language is in English.

Follow Regional Legal Requirements

• US (TCPA): Opt-in must be explicit. No pre-checked boxes.

• Canada (CASL): Consent must be prior and verifiable.

• EU (GDPR): Requires active consent and clear data use disclosure.

Enable Smart Sending & Quiet Hours

Klaviyo offers:

• Smart Sending: Prevents texts to recipients messaged within X hours

• Quiet Hours: Suppresses sends during custom windows (e.g., 9 PM–10 AM). Applies only to flows and campaigns.

For a deeper dive into regional compliance, setup, and testing tips, check out our full guide on Klaviyo SMS Quiet Hours.

Always Include Clear Opt-Out Instructions

Every SMS must include “Reply STOP to unsubscribe.” Klaviyo handles this by default.

Source: Klaviyo 

Flow Examples to Build Now

Klaviyo SMS flows let you automate personalised, real-time communication across the customer journey—from welcome to win-back. Here are 9 proven automations every DTC brand should build to boost retention and revenue.

1. Welcome Series

Trigger: SMS opt-in via pop-up, embedded form, or checkout
What to Include:

• A warm greeting and brand tone

• A discount code or offer promised during sign-up

• What to expect from future messages

Why It Works: First impressions matter. SMS has a 98% open rate—make the first one count to convert new subscribers quickly.

Source: Mailcharts

See how to personalise welcome automations in our guide on how to build a high-converting Klaviyo welcome flow.

2. Abandoned Cart

Trigger: Customer adds to cart but does not purchase after 1–4 hours
What to Include:

• Reminder with direct cart link

• Scarcity language (“Selling fast!”)

• Light incentive (“Use code SAVE10”)

Why It Works: This is one of the highest-ROI flows. Klaviyo recommends sending 1–2 SMS reminders with urgency and click-through optimisation.

Source: Andzen

Explore more tips in our guide to high-performing browse and abandoned cart flows.

3. Shipping Updates

Trigger: Order placed → shipped → delivered
What to Include:

• Confirmation message with order number

• Tracking link

• Delivery confirmation

Why It Works: Reduces “Where is my order?” tickets and builds trust post-purchase. Klaviyo integrates directly with platforms like Shopify for real-time data.

Source: Malomo

4. Post-Purchase Flow

Trigger: Order fulfilled
What to Include:

• Thank-you message

• Add-on product suggestion or bundle

• Follow-up review request or care tips

Why It Works: Turns one-time buyers into repeat customers. Use SMS first for immediacy, followed by email with rich product detail.

Source: Klaviyo

Learn how to optimise your post-purchase automations in our blog on post-purchase email flows.

5. Win-Back

Trigger: Last purchase was 60+ or 90+ days ago
What to Include:

• Exclusive “we miss you” offer

• Quick-buy link to a recent favourite

Why It Works: Helps retain drifting customers and protect LTV. Use segment filters to exclude active buyers.

Source: SimpleTexting

See examples of Klaviyo win-back and re-engagement flows in action.

6. VIP Flow

Trigger: Customer enters VIP segment based on LTV or order count
What to Include:

•  Early access to product drops

•  Private sales or loyalty rewards

Why It Works: Rewards your most valuable customers, deepens brand affinity, and increases repeat purchase rate. Use Klaviyo predictive analytics or Shopify tags to build dynamic VIP segments.

Source: Recart

7. Back-in-Stock

 Trigger: Item restocked + profile viewed or waitlisted the product
What to Include:

•  Product-specific alert with urgency

•  Direct link to checkout page

 Why It Works: Converts high-intent shoppers who've shown interest before. Personalised alerts drive fast conversions and reduce missed opportunities.

Source: Message Media

For full setup steps, visit our guide on how to build a Klaviyo back-in-stock flow.

8. Price Drop

Trigger: Product in wishlist or viewed previously drops in price
What to Include:

• Discount announcement with product name

• “Shop now” link to PDP or cart

Why It Works: Shoppers who viewed but didn’t buy are price-sensitive. SMS lets you strike while the offer is hot—before competitors do. Use Klaviyo’s Price Drop trigger to automate this with Shopify or WooCommerce.

Source: Klaviyo 

9. Abandoned Checkout

Trigger: Customer reaches checkout but doesn’t complete purchase after 1 hour
What to Include:

• Reminder with cart link

• Optional urgency (“Only 3 left”)

• Incentive or free shipping

Why It Works: High-intent users need a nudge. SMS cuts through noise better than email with a 90% read rate in under 3 minutes, making it ideal for fast recovery.

Source: Yotpo

See our full Klaviyo abandoned cart and checkout flow guide for setup tips and conversion strategies.

Personalise Klaviyo SMS Flows with Smart Data

Personalisation turns SMS from generic to high-impact. Klaviyo lets you use real-time profile and behavioural data to send messages that feel timely and relevant.

Use Profile Properties

Insert dynamic fields like:

• Always define a fallback (e.g. {{ first_name|default:'there' }}) to avoid blank fields in messages.

• Great for birthday offers, local updates, and VIP recognition

Leverage Behavioural Data

Trigger messages from:

• Viewed products

• Added-to-cart items

• Email or site activity

Segment by Lifecycle Stage

Group users by:

• New vs repeat customers

• VIP vs low LTV

• Engaged vs at-risk

Then tailor messaging: education for new subscribers and exclusive perks for VIPs.

A/B Test SMS Flows to Improve Results

Split testing (A/B testing) is essential to optimise your SMS flows — not guesswork. See our full guide on how to run and analyse A/B tests in Klaviyo.

What to Test

• Timing: Immediate vs delayed sends (e.g. 1hr vs 3hr after cart abandonment)

• CTA Wording: “Shop Now” vs “Grab Your Deal”

• Message Style: Personalised vs generic tone

• Incentives: No offer vs 10% off

• Send Channel: SMS-only vs SMS + email combo

Track Key Metrics

• Click-through rate (CTR)

• Conversion rate

• Opt-out rate (critical for compliance and message quality)

• Revenue per recipient / ROI

Best Practices

• Run tests for at least 2 weeks or until statistical significance is reached

• Only test one variable at a time

• Avoid testing during sales periods unless that’s your target window

Why It Works

Even small message tweaks can lead to large lifts in CTR and revenue. For example, Klaviyo benchmarks show a 10–30% performance difference between top and bottom variants in high-volume SMS flows.

Advanced Flow Logic to Supercharge Klaviyo SMS ROI

Once your core SMS flows are live, adding advanced logic in Klaviyo helps scale personalisation, avoid fatigue, and maximise ROI.

Use Conditional Splits

Target segments with relevant messaging by:

• Splitting based on location, gender, or loyalty tier

• Showing different products for high vs low lifetime value (LTV)

• Customising copy for first-time vs repeat customers

Add Smart Delays

Improve timing and reduce overlap:

• Delay SMS if a customer recently got an email or SMS

• Wait a few days after order delivery before upselling

• Use “Wait until X days after the event” for controlled cadence

Tip: Turn on Smart Sending to automatically skip messages if the user was recently contacted.

Source: Klaviyo 

Trigger Flows from Real-Time Behaviour

Use behavioural and zero-party data to personalise:

• Viewed product? Trigger a back-in-stock alert

• Completed a quiz? Send tailored SMS using Octane AI or Typeform responses

• Abandoned checkout? Trigger SMS faster than email for better recovery

Combine SMS and Email for Cross-Channel Impact

Blend SMS urgency with email depth:

• Use SMS for time-sensitive actions (flash sales, stock alerts)

• Use email for visuals, storytelling, or bundles

• Add logic like “Has clicked email in last 7 days = false” to reduce duplication

Why It Works

Flows with layered filters and splits drive relevance, reduce opt-outs, and boost performance. Klaviyo users applying multi-branch logic often report 20–40% increases in per-message revenue compared to generic flows.

When to Use SMS vs Email

FAQs

1. How many SMS flows should I start with in Klaviyo?

• Start with 3–4 core flows: Welcome, Abandoned Cart, Post-Purchase, and Win-Back. Expand to VIP and Back-in-Stock as your list grows.

2. Can I send both email and SMS in the same Klaviyo flow?

• Yes. Klaviyo lets you mix channels within a flow. Use SMS for urgency and email for visuals and longer-form content.

3. How do I stay compliant when sending SMS?

• Use Klaviyo’s built-in consent tools. Always get opt-in, include opt-out language (e.g. "Reply STOP to unsubscribe"), and respect quiet hours.

4. How do I test if my SMS flow is working?

• Use Klaviyo’s preview and test message features, monitor click-through rates, and A/B test message timing or offers.

5. What’s a good SMS conversion rate?

• It varies by flow, but a 10–15% click-through rate and 5–8% conversion rate are strong benchmarks for abandoned cart or price drop SMS.

Conclusion

SMS isn’t just a nice-to-have—it’s a retention superpower. With 90% of messages read in under 3 minutes and only 2–3 brand opt-ins per consumer, every text must deliver value fast. Klaviyo SMS flows give you that edge—automating timely, targeted messages that reach customers exactly when they’re ready to act. 

Whether it’s a gentle nudge after cart abandonment or a VIP-first product drop, SMS keeps your brand top of mind and your LTV growing. Start with the flows that matter most, layer in personalisation, and let Klaviyo do the heavy lifting. It’s not about more messages—it’s about smarter ones.

Key Takeaways

• SMS Drives Fast Results: Over 90% of SMS messages are read within 3 minutes—ideal for urgent or time-sensitive flows.

• Start With High-Impact Automations: Focus on Welcome, Abandoned Cart, Post-Purchase, and Win-Back to build your revenue foundation.

• Use Email & SMS Together: Combine the immediacy of SMS with the depth of email for better conversion and customer experience.

• Stay Compliant at Every Step: Always get explicit opt-in, include unsubscribe options, and respect quiet hours to avoid penalties.

• Personalised Flows Increase LTV: Target users by behaviour, purchase history, or VIP status to make each message count.

• Klaviyo Simplifies Execution: Native integrations, real-time triggers, and drag-and-drop flow builders make setup seamless—even for lean teams.

Worried your Klaviyo SMS flows are annoying customers, not converting them?

Our experts will review your setup for compliance, timing, and personalisation, so your texts build trust and boost revenue. Click here to book your free SMS audit today and start turning texts into revenue.