Klaviyo SMS Marketing: Setup, Pricing, Flows and Consent

Klaviyo SMS marketing means sending text messages from the same platform, profile and flow builder as your email. You collect SMS consent with Klaviyo forms or at checkout, send from a toll-free number, short code or sender ID depending on the country, and build SMS steps into the flows you already run. Billing moved from credits to dollar-based rates in 2026.

This guide covers what we set up on every Klaviyo SMS build: the sending number, the pricing, consent, quiet hours, and the flows that earn their keep. Everything about Klaviyo’s product is checked against Klaviyo’s help centre as of September 2026. If you’re new to the channel, start with our SMS marketing guide.

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What Klaviyo SMS includes

Klaviyo started as an email platform and added SMS later, but it’s now a full mobile messaging product sitting on the same customer profile. As of September 2026 that includes:

• SMS and MMS in 23 countries (MMS only in the US, Canada and Australia, and only on certain number types).
• RCS, generally available since February 2026 in the US, UK and several European markets, with automatic SMS fallback.
• WhatsApp marketing messages, billed per delivered template message. Meta has blocked WhatsApp marketing messages to US numbers since April 2025, so this is for non-US audiences.
• Two-way conversations, which land as tickets in Klaviyo’s helpdesk, plus rule-based keyword and quiz automations.
• Transactional SMS (order, shipping and delivery updates) for paid accounts on Shopify, subject to Klaviyo’s approval.
• AI tools: an SMS copy assistant and Klaviyo’s Customer Agent, which can answer customers over SMS on two-way-enabled numbers.

The real advantage isn’t any single feature. It’s that an SMS subscriber is the same profile as the email subscriber, so one flow can decide which channel to use, one segment can target both, and one attribution model reports both. We cover how to run the two together in Email + SMS Marketing in Klaviyo.

Is Klaviyo SMS good enough, or do you need Postscript or Attentive?

For most ecommerce brands, Klaviyo SMS is enough. Specialists still go deeper on SMS-only features: Postscript on Shopify-native data and conversational selling, Attentive on enterprise-scale SMS programs. If SMS is your dominant retention channel, a specialist can be worth the second platform. If it’s a strong second channel next to email, the unified stack usually wins. Our Klaviyo vs Postscript and Klaviyo vs Attentive comparisons go through it honestly, and our best SMS marketing platforms round-up covers the wider field.

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How much Klaviyo SMS costs in 2026

Klaviyo changed SMS billing this year, and a lot of the pricing information online is now out of date.

Credits have been replaced by dollars. Per Klaviyo’s billing FAQ, new and free-plan customers moved to dollar-based mobile messaging tiers from July 13, 2026, and existing paid customers move at their first billing cycle after August 13, 2026. If your old credit tier doesn’t exist in the new structure, you move to the closest lower tier.

How a send is priced. Klaviyo’s rates article gives the formula as rate × recipients × message segments. Its billing help says carrier fees are built into the rate rather than billed as separate line items, and unused spend doesn’t roll over. Opt-in confirmation messages, STOP and HELP replies, and skipped messages aren’t billed.

What it costs to start. Klaviyo’s free plan includes $5 of mobile messaging a month (region and provider dependent). Beyond that, you add a monthly mobile messaging tier to your plan. As of September 2026, Klaviyo’s US pricing calculator shows:

Monthly US volume (toll-free number)	Monthly cost
1,000 SMS	$15
5,000 SMS	$70
10,000 SMS	$125
1,000 MMS	$45

Short codes are slightly cheaper per message (10,000 US SMS was $115 a month) but carry their own monthly fee. International sends cost more: 1,000 SMS was $30 a month to Australia and $70 to the UK in the same calculator. Your account’s exact rates are under Settings > Billing > Account Usage.

What moves the bill:

• Country. International messages cost more than US messages. Under the legacy credit system, a UK SMS segment cost five times a US one and an Australian segment four times, which gives a sense of the spread.
• Number type. In the US and Canada, rates differ between toll-free and short code.
• Segments. A standard SMS segment holds 160 characters. One emoji or special character drops that to 70, and long messages split into segments of about 153 characters. Each segment is billed.
• MMS and RCS. MMS costs more than SMS. Basic RCS generally costs the same as SMS; rich RCS costs more.

The practical takeaway: write texts that fit in one segment, avoid emoji unless they earn their place, and keep MMS for launches where the image is the message. Our Klaviyo pricing guide covers the email side of the bill.

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Countries and sending numbers

Which number you send from depends on the country. As of September 2026, Klaviyo supports SMS in the US (50 states), Canada, Mexico (international rates only), 18 European countries including the UK, Ireland, Germany, France, the Netherlands and the Nordics, plus Australia and New Zealand.

Country	Default (free) sender	Paid option	MMS	Registration
United States	Toll-free number	Short code (vanity or non-vanity)	Toll-free and short code	Toll-free verification, about 2 to 5 business days
Canada	Toll-free number (shared with US)	Vanity short code	Toll-free only	Toll-free verification
United Kingdom	Branded sender ID	Long code also available	No	Sender ID activates immediately in Klaviyo
Australia	Branded sender ID	Long code	Long code only	Register the sender ID on the ACMA SMS Sender ID Register (since July 1, 2026, unregistered IDs display as “Unverified”); about 7 to 10 business days in Klaviyo
New Zealand	Short code (vanity)	–	No	Around 5 to 6 weeks

A few things that catch brands out:

• 10DLC isn’t the default in Klaviyo. Most SMS tools start US senders on a 10DLC long code; Klaviyo starts them on a toll-free number, with a short code as the upgrade. Klaviyo’s long code guide doesn’t list the US (its countries table is less clear), so if you’re migrating from a platform that used a 10DLC number, plan for a new sender and confirm the options with Klaviyo.
• Branded sender IDs are one-way. A sender ID like “BRAND” can’t receive replies, so keywords, two-way conversations and tap-to-text sign-ups don’t work on it. In the UK and Australia, choose a long code if you want replies.
• Short codes take months. Klaviyo quotes 8 to 12 weeks for a new US short code, and 12 to 16 weeks in Canada and the UK, counted from when Klaviyo submits the application to carriers. Short codes carry an extra monthly cost that varies by country. Don’t start the process in October and expect it for Black Friday.
• Don’t send before verification. Klaviyo tells you not to send from a toll-free number while verification is pending, and not to turn forms or flows live until it’s approved.

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How to set up SMS in Klaviyo

Only Owners, Admins and Managers can set up SMS, and not every industry is eligible (SHAFT categories, meaning sex, hate, alcohol, firearms and tobacco, face extra restrictions). The setup itself is quick; the verification is what takes time.

1. Go to Settings > SMS (from your account name in the lower left) and choose to set up SMS, or add a country if SMS is already on.
2. Select your countries. Only add countries you’ll genuinely send to, since each has its own rules.
3. Enter your company details. The legal name, website, registered address and business registration number must match your official records. Mismatches are the most common reason verification stalls.
4. Pick a sending number per country. Start with the free default (toll-free in the US and Canada, sender ID elsewhere) unless you already know you need a short code or two-way messaging on a long code.
5. Complete verification or registration. Toll-free verification in the US and Canada, the ACMA SMS Sender ID Register in Australia, and local registration in Ireland and Spain.
6. Set your compliance settings before anything goes live: company prefix, opt-out wording (it must include STOP), quiet hours and the confirmation reply.
7. Collect or import subscribers. Build a sign-up form, or upload an existing SMS list only if you hold documented consent for every number on it.

Then test. Text STOP, HELP and your subscribe keyword to your own number and check every reply before a customer sees one.

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Collecting SMS consent in Klaviyo

Consent is where SMS programs live or die, legally and commercially. Klaviyo gives you several opt-in routes:

• Sign-up forms. A phone number field (single opt-in), tap-to-text on mobile (opens a pre-filled text to your number), or Klaviyo’s Smart Opt-in, which confirms the number with a one-time passcode. Smart Opt-in needs a paid SMS plan. Tap-to-text doesn’t work with branded sender IDs.
• Checkout. Klaviyo syncs SMS consent from Shopify, BigCommerce, WooCommerce, Magento 2 and PrestaShop checkouts.
• Keywords. Text-to-join keywords (3 to 20 characters) on long codes, short codes and toll-free numbers, useful for packaging inserts, QR codes and in-store signage.
• API, for custom sign-up flows and other tools.

The rules we apply on every build:

• SMS consent must be optional and separate. Klaviyo’s own guidance is that SMS must not appear to be required. Never pre-tick a box.
• Put the disclosure next to the field. Klaviyo provides a default disclosure template. It names the company, says the texts may be sent by autodialer and that consent isn’t a condition of purchase, mentions message and data rates and variable frequency, explains how to opt out, and links your privacy policy and terms. Use it and adapt it to your brand.
• Use double opt-in. Klaviyo recommends double opt-in for SMS lists and makes it the default. It costs you a few sign-ups and protects you from typos, fake numbers and disputes. For branded sender IDs the confirmation text is skipped automatically.
• Go email first, then phone. Klaviyo recommends multi-step forms: capture email on step one, ask for the phone number on step two. You keep the email even if they skip SMS.

Shopify checkout sync, step by step: in Klaviyo, go to Integrations > Shopify > Sync settings and turn on syncing Shopify SMS subscribers to Klaviyo, choosing a dedicated SMS list. In Shopify, go to Settings > Checkout > Marketing options and enable SMS. Consent syncs once the customer enters their number, ticks the box and continues to shipping, even if they never finish the order, which is exactly what makes the abandoned checkout text possible.

Keywords and opt-outs. Klaviyo automatically handles the standard compliance keywords (STOP, QUIT, END, CANCEL, HELP, INFO, START and others), replies and updates consent. You can edit most auto-replies, except opt-out replies in the US and Canada. The full picture of what the law requires, including the FCC’s 2025 opt-out rules, is in our SMS marketing compliance guide.

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Quiet hours and smart sending

Quiet hours. By default, Klaviyo holds marketing SMS between 8 p.m. and 11 a.m., using Eastern Time for the US and Canada, UK time for the UK, and Australian Eastern Time for Australia. In the US and Canada, flows use the recipient’s area code by default. Flow messages that land in quiet hours wait in a queue and go out at the next allowed time. Transactional messages aren’t held by default (except in France).

Klaviyo’s default is deliberately tighter than the law. The usual legal window is 8 a.m. to 9 p.m. in the recipient’s time zone, and some US states are stricter; Florida, for example, limits sending to 8 a.m. to 8 p.m. If you widen Klaviyo’s window, stay inside the strictest rule that applies to your list.

Smart sending. Klaviyo’s SMS smart sending window defaults to 24 hours (email’s is 16), and each channel is tracked separately. That means an SMS campaign won’t hit someone who got an SMS in the last 24 hours, but it won’t stop an SMS landing an hour after an email. Plan cross-channel spacing in the flow itself.

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The SMS flows to build first

Klaviyo’s own recommendation is to add SMS to three flows first: welcome, abandoned cart and browse abandonment. We agree, with back in stock and post-purchase close behind.

Welcome. Klaviyo suggests a separate SMS welcome flow from your email one, and three or four texts a few days apart. Text one delivers what the form promised. Later texts can share a contact card (vCard) so your number gets saved, point to bestsellers, and remind non-buyers once before the offer expires. Example copy is in our SMS marketing examples.

Abandoned cart and checkout. In the US, Klaviyo’s abandoned cart SMS rules are strict: the list must be double opt-in, you’re limited to one SMS per recipient per abandonment, and it must be sent within 48 hours of the trigger. Make that one text count: name the product, include one link, and let email carry the rest of the sequence.

Browse abandonment. Send the text a few hours after the browse email, not at the same time, and only to engaged subscribers. Browse intent is weaker than cart intent, so keep the frequency low.

Back in stock. Waitlisters asked to be told. Use a consent split and the product from the back-in-stock event. See our back in stock and price drop flows guide.

Post-purchase. One text is usually enough: a how-to-use tip or a delivery heads-up. Keep the cross-sell for email.

How to add SMS to a flow. Drag an SMS action onto the flow canvas and edit it. To route people by channel, add a conditional split on whether someone can receive SMS marketing, and send the email on one branch and the text on the other. That keeps SMS for subscribers who can receive it without doubling up on everyone else.

Transactional SMS. Order, fulfilment, shipping and delivery texts can be sent as transactional messages, which don’t need marketing consent. In Klaviyo this is available to paid accounts on Shopify, not to alcohol or firearms brands, and each message needs Klaviyo’s approval (up to 24 hours). Editing an approved message removes its transactional status, and transactional messages must not contain marketing content.

For supplement and replenishment brands, a replenishment text timed to the product’s usage cycle is often the best-performing flow after the cart. We cover the timing logic in 10 email flows for supplement brands.

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Campaigns: how often, and to whom

Our working guidance is four to six SMS campaigns a month for most ecommerce brands, with flows on top. Send campaigns to segments that have earned them (recent clickers, recent buyers, VIPs) rather than the whole SMS list, and put SMS in the same calendar as email so the two don’t land on top of each other.

Use branded links rather than generic shorteners. Klaviyo offers a branded Klaviyo link or a custom subdomain on your own domain, and a recognisable domain is more trustworthy than a random short URL.

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Measuring Klaviyo SMS performance

Klaviyo’s help centre publishes performance tiers for SMS campaigns in the US (as of its October 2025 update, and it notes that ranges vary by industry):

Metric	Great	Good	Room for improvement	Critical
Click rate	14.6% or more	8.9% to 14.5%	6.0% to 8.8%	Below 5.9%
Conversion rate	2.1% or more	1.0% to 2.0%	0.5% to 0.9%	Below 0.5%
Unsubscribe rate	Below 0.5%	0.6% to 1.4%	1.5% to 1.9%	2.0% or more
Revenue per recipient	$2.42 or more	$0.66 to $2.41	$0.18 to $0.65	Below $0.18

Klaviyo’s 2026 SMS benchmark report (across more than 183,000 Klaviyo customers) adds the number that should shape your plan: SMS flows made up 7.6% of SMS sends but drove 45.2% of SMS revenue. Flows first, campaigns second.

The metrics we watch weekly: revenue per recipient against the cost per message, unsubscribe rate per send, and list growth net of unsubscribes. Click rate on its own flatters a program that’s burning its list.

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Common Klaviyo SMS mistakes

• Budgeting on old credit pricing. Pricing guides written before July 2026 quote credits. Check your dollar rates in the account.
• Launching before verification clears. Sending from an unverified toll-free number gets messages filtered.
• Emoji in every text. One emoji can turn a one-segment message into a three-segment one.
• Firing SMS and email at the same moment. Stagger them in the flow.
• Using a branded sender ID and expecting replies. Pick a long code if two-way matters in the UK or Australia.
• Importing a list without consent records. If you can’t show where and how each number opted in, don’t text it.

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Want Klaviyo SMS set up properly the first time?

We build Klaviyo SMS programs for ecommerce brands: sender registration, compliant consent, SMS steps inside the flows you already run, and reporting that puts SMS revenue next to its cost. If you’re moving from Attentive or Postscript, we handle the migration with consent records intact. Not sure where your current setup stands? Start with a free Klaviyo audit.