Migrate to Klaviyo before BFCM: everything you need to know

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Considering a migration to Klaviyo before Black Friday Cyber Monday (BFCM)? As the only CRM built specifically for B2C businesses, Klaviyo offers unparalleled capabilities for managing your most critical sales period of the year. But timing and implementation are everything when it comes to pre-BFCM migrations.

We’ve gathered insights from leading migration experts to answer your most pressing questions about making the switch to Klaviyo before the holiday rush:

• Shannon Santorineos, VP of customer success, and Tyler Leeth, martech lead at RedVan Workshop, a leading Salesforce, Shopify, and Klaviyo agency with 100% onshore developers.
• Jamie Smith, director of technical solutions at Anatta, a digital consultancy that precision engineers transformative commerce solutions for enterprise partners
• Brian Campbell, CEO of CrucialPoint Agency, a retention marketing agency based in Salt Lake City, Utah, operating throughout the U.S.
• Ben Zettler, CEO of Zettler Digital, a performance marketing agency based in the NYC metropolitan area.

Whether you’re worried about deliverability, concerned about downtime, or wondering if you have enough time, this comprehensive FAQ will guide you through every aspect of a successful pre-BFCM migration.

Timeline and planning

What’s the recommended timeline for completing a full Klaviyo migration before BFCM?

Experts recommend at least a month to complete your migration to Klaviyo.

“It’s really going to be unique to each migration,” says Leeth. “No two migrations are the same, but anywhere between 4 and 6 weeks would be a typical timeframe.”

Campbell says the length of time needed for a migration depends on list size.

• Brands with lists under 50,000 subscribers likely need a minimum of 4 weeks.
• Those with lists between 50,000 and 250,000 need 5–6 weeks.
• Brands with large lists of 250,000+ should plan for 6–8 weeks.

If you get a late start, consider:

• Working with experienced Klaviyo partner
• Focusing on core functionality only
• Planning extensive post-BFCM optimization
• Having detailed fallback plans
• Keeping your old ESP as backup initially

“If brands have a strong partner, there to catch you if you fall, the migration to Klaviyo can go very quickly and smoothly in our experience,” notes Santorineos.

If brands have a strong agency partner, there to catch you if you fall, the migration to Klaviyo can go very quickly and smoothly.

What’s the latest we can start migration and still be ready for BFCM?

Experts generally recommend mid-August to mid-September as a good timeframe to get set up in Klaviyo ahead of BFCM.

Completing your migration in August gives your brand plenty of time to:

• Adjust to the new normal.
• Get used to how things work in Klaviyo.
• Learn how your processes need to change.
• Get very comfortable with the new tools before the big weekend.

Smith is comfortable with a shorter period: “The latest practical time to start a simple Klaviyo migration is early to mid-September. Starting later than this risks insufficient time for critical deliverability warm-up and testing, especially for larger email lists.”

Santorineos adds that IP warming is also critical: “The longer you have, the better.”

Migration reminder: Email takes longer than SMS to migrate. “Because there’s no warming period for SMS, you can start sending to your full list right away,” says Savannah Mazola, SMS digital strategist at Klaviyo.

How do you prioritize migration tasks when working under tight BFCM deadlines?

Of course, every brand is different. Priorities will shift depending on list size, which features and capabilities you’re planning to use, and your marketing goals.

Leeth asks brands one guiding question:

What are the most critical, revenue-impacting campaigns and segments that are going to get the most attention and have the most impact once they’re migrated?

The RedVan Workshop team uses the answer to make their to-do list.

At Anatta, Smith uses a “core to enhanced” strategy to prioritize critical tasks like setting up:

• Sign-up forms
• Welcome series
• Abandoned cart flows
• Key segments
• Transactional emails

“Advanced flows, lesser-used segments, and email template redesigns can be optimized after your initial migration,” Smith says. “‘Core-to-enhanced’ ensures you’re functional and revenue-ready first, then optimized.”

Advanced flows, lesser-used segments, and email template redesigns can be optimized after your initial migrations. Our approach makes sure you’re functional and revenue-ready first, then optimized.

Should we migrate all at once or gradually?

Smith recommends a phased “switch by channel” approach for most merchants on Shopify, starting with your most impactful channels, then beginning the migration with critical flows like welcome sequences, then cart abandonment. This method minimizes disruptions and ensures continuous engagement with your subscribers.

What SMS flows should I have live before BFCM?

• SMS Welcome Series (immediate coupon or early access offer).
• Abandoned Cart (1 SMS reminders with urgency).
• Browse Abandonment (personalized reminder with product link).
• Post-Purchase Thank You (tease upcoming BFCM VIP deals).
• Back-in-Stock Alerts (great for hot items likely to sell out).
• Price Drop Alerts (notify your customers in real time when prices drop significantly)

What are the best SMS campaign types for BFCM?

• VIP Early Access: Text subscribers before anyone else.
• Doorbuster Announcements: “Hurry—only 4 hours left to save 50%.”
• Flash Sales: Short windows (2–6 hours) to create urgency.
• Restock Alerts: “It’s back! Get it before it sells out again.”
• Cart Recovery Campaigns: Send a follow-up to those who didn’t purchase.

When should I start sending BFCM-related SMS?

• 2–3 weeks before: Build hype with countdowns and grow your list with opt-in promos.
• 1 week before: Send VIP early access invitations.
• BFCM weekend: Send 1–2 SMS per major sale day (morning and evening).
• Cyber Monday: Announce last-chance deals.
• Post-BFCM: Thank customers + offer extended sale or holiday deals.

What red flags do you look for when assessing whether a brand should attempt a pre-BFCM migration?

Campbell stresses that a migration to Klaviyo won’t fix a company’s problems around branding or acquisition. “Your team needs to be truly ready for migration. Start with a deepdive audit to uncover and fix existing issues, then map out a clear roadmap for the next 3–5 years (or at least the next 12 months). The more you can define your future data needs now, the smoother and more efficient your post-migration period will be,” he says.

The more you can define your future data needs now, the smoother and more efficient your post-migration period will be.

Smith lists some specific red flags:

• Understaffed email teams
• Absence of an internal email manager
• Poor historical list hygiene
• Inadequate attribution tracking

“If Anatta identifies multiple red flags, we advise delaying migration until after the holidays,” Smith says.

Leeth takes a look at the big picture and examines the entire tech stack. “If there’s a lot of risk, or stability concerns, we weigh that against how critical BFCM is to the brand.”

Technical concerns

What are the most common technical hurdles you encounter when migrating ecommerce integrations before BFCM?

Common technical hurdles experts encounter include:

• Complex integrations with third-party systems
• Broken sign-up forms
• Missing custom properties
• Data overwrites from dual ESP connections

“To minimize disruption,” Smith recommends, “follow rigorous QA processes and use parallel testing environments.”

Leeth and Santorineos have a QA team that’s well-versed in end-to-end testing as well as the various ways people sign up. “With myriad ways for people to sign up for marketing messaging, subscriber loss is possible,” they say. “We make sure those sign-ups land in Klaviyo.”

“QA is where migrations fall apart,” says Zettler. “Every flow, segment, and campaign needs to be tested in a real inbox, not just ‘previewed.’ Check dynamic content, and make sure you don’t have broken links or ‘Hi, first_name.’ Look at mobile and desktop. Every minute spent here saves you days of chaos later.”

QA is where migrations fall apart.

How should we approach migrating complex automations/flows, especially welcome series and abandoned cart sequences?

At RedVan Workshop, the team investigates a few core issues ahead of migrating the more complex flows:

• How is the brand’s CRM strategy working today?
• What are the challenges their current solution is giving them?
• What are the brand’s marketing goals moving forward?

“The benefit of a migration is that brands get a blank slate mentality,” Leeth says. “We can optimize Klaviyo to overcome the challenges the legacy system gave us.”

We can optimize Klaviyo to overcome the challenges the legacy system gave us.

“A fresh start is much better than bringing all of your baggage along with you,” Santorineos adds.

Smith details their approach: “Anatta maps your existing automation logic into Klaviyo, enhancing it with optimized conditions and targeted segments before publishing. We prioritize welcome and abandoned cart flows and rigorously test to ensure seamless performance and maximize BFCM revenue.”

Migration pro tip: Get familiar with predictive analytics ahead of BFCM.

Will we lose our email history and subscriber data?

The short answer is no.

“Klaviyo makes it very easy to get that email history and subscriber data over with the integrations that they have,” says Leeth.

“Your subscriber data, including engagement metrics and tags, will be safely migrated to Klaviyo,” Smith agrees. “While historical open and click data may be limited during the transition, Klaviyo predictive analytics quickly bridges this gap, helping you maintain effective targeting and personalization immediately after migration.”

Klaviyo predictive analytics bridges the gap, helping you maintain effective personalization immediately after the migration.

Santorineos recommends you don’t wait until the contract for your existing platform is ending, in order “to give yourself a little bit of a buffer.”

What happens to our current email automations during migration?

You have a few options for your current automations.

At Anatta, Smith shares that “your existing email automations remain live until their Klaviyo replacements have been thoroughly tested. This approach prevents any gaps in your lifecycle marketing efforts.”

RedVan Workshop sometimes pauses email automations on the legacy tool and then launches on Klaivyo. “If there were any issues, you could resume in your other system until you’re comfortable launching on Klaviyo,” explains Leeth.

Will our sign-up forms stop working during migration?

“Your sign-up forms will be fine if you follow a well-planned migration process,” Smith says. “Migrating without downtime requires careful auditing and validation of all sign-up forms, including pop-ups, footer forms, and check-out opt-ins. You should also thoroughly test form routing to Klaviyo to ensure no subscriber loss or downtime.”

How do we ensure our Shopify/WooCommerce integration works correctly?

“Work with a partner that’s also a commerce expert,” advises Santorineos.

Smith provides technical guidance: “Leverage Klaviyo’s native Shopify/WooCommerce integrations to enable real-time synchronization. Extensive testing with staged data validates key events—such as orders, customers, and products—to ensure flawless integration before going live.”

List hygiene

Before importing your email list to Klaviyo, thorough cleaning is essential for maintaining deliverability and maximizing your BFCM performance.

As Zettler emphasizes: “Data cleanliness is non-negotiable. It’s not just about removing bounces. You need to hunt down and suppress dead emails from old contests, bots, fakes, and duplicates from messy imports. If you skip this, you’ll tank your sender reputation on Day 1.”

Data cleanliness is non-negotiable.

What are the essential list cleaning tasks?

1. Remove inactive subscribers

Remove subscribers unengaged for 12+ months:

• Export engagement data from your current ESP.
• Identify subscribers with no opens/clicks in the past year.
• Create a suppression list for these contacts.

“Always clean your email list before migration,” Smith recommends. “Removing inactive subscribers (e.g., those unengaged for over 12 months) enhances deliverability, engagement rates, and overall email ROI post-migration.”

Removing inactive subscribers enhances deliverability, engagement rates, and overall email ROI post-migration.

2. Export and import suppression lists

Export the following suppression data and import it into Klaviyo as exclusion lists:

• Hard bounces (permanent delivery failures)
• Soft bounces (temporary issues that became permanent)
• Manual unsubscribes
• Spam/abuse complaints
• Global suppression lists

“We advise exporting suppression data (unsubscribes, bounces, spam reports) from your previous email provider and importing that data into Klaviyo as exclusion lists,” Smith explains. “This step ensures compliance, preserves deliverability, and prevents common migration pitfalls. Missing this step is a common risk in Klaviyo migrations.”

Export suppression data from your previous provider and import that data into Klaviyo as exclusion lists. Missing this step is a common risk.

3. Eliminate low-quality contacts

Target these problematic segments:

• Contest/giveaway entries (often low engagement)
• Purchased or rented lists (prohibited by Klaviyo)
• Role-based emails (info@, admin@, sales@)
• Obviously fake emails (test@test.com, etc.)
• Duplicate entries with different formatting

4. Validate email formatting

Check for common issues:

• Missing @ symbols
• Invalid domain extensions
• Extra spaces or special characters
• Incomplete email addresses

5. Segment your best performers

Identify your most engaged subscribers for strategic warm-up:

• Regular openers (opened emails in last 30–90 days)
• Recent clickers
• Recent purchasers
• High-lifetime-value customers

What if my list size shrinks?

Don’t be afraid to significantly reduce your list size. A smaller, more engaged list will outperform a large, unengaged one—especially crucial for BFCM success.

Get your deliverability in order ahead of BFCM

Klaviyo global deliverability experts share 5 tips for making sure yours is in tip-top shape ahead of the big weekend.

Read more

Template and creative migration

What’s your process for migrating email templates while ensuring they’re optimized for Klaviyo’s capabilities?

“I always push for recreating everything in Klaviyo’s editor,” says Leeth. “If you copy and paste your existing emails, you can’t make use of all the awesome features that Klaviyo provides you. If you build it right the first time directly in Klaviyo, you’re going to have all those tools available to you.”

I always push for recreating everything in Klaviyo’s editor.

Smith details Anatta’s process: “We conduct an audit of your existing templates, rebuild them in Klaviyo’s intuitive editor, and optimize each template for mobile responsiveness, deliverability, and accessibility. Post-migration, we recommend A/B testing to improve performance further.”

How do you approach recreating dynamic content and personalization elements in Klaviyo’s system?

“Anatta recreates logic using Klaviyo’s powerful templating language and profile variables,” Smith explains. “Some ESPs use proprietary merge tags. Mapping these correctly is essential.”

Cost and ROI

How does Klaviyo’s pricing compare to our current ESP?

“The cost of maintaining and managing the CRM creates a savings that’s ongoing,” says Santorineos.

The cost of maintaining and managing the CRM creates a savings that’s ongoing.

“The technical resource cost is a lot less,” Leeth adds. “Marketers can do a lot more on their own.”

What’s the learning curve for our team?

“Honestly, I feel like it’s pretty intuitive,” says Leeth. “People seem to pick up on it very quickly.”

“Ease of use with Klaviyo is usually light years ahead of what brands have been using from a UX perspective and that’s a refreshing change,” adds Santorineos.

Smith recommends that brands “expect a moderate learning curve, especially for mastering flows, segmentation, and analytics.”

Ease of use with Klaviyo is usually light years ahead of what brands are used to.

Data migration and segmentation

How do you preserve historical data and engagement metrics during migration?

All of our experts recommend manually building your segments in Klaviyo during the migration. “It’s a good opportunity to reset,” says Campbell.

“Segmentation logic can get lost in translation,” Zettler says. “Your old platform’s logic for ‘engaged’ or ‘VIP’ segments doesn’t necessarily come over. Segments are built on event data that usually doesn’t make the jump.”

For that reason, “it’s best to rebuild each one manually in Klaviyo, mapping rules and sometimes starting from scratch,” Zettler adds. “Test before trusting. Wrong group, wrong message, instant performance drop.”

Test before trusting. Wrong group, wrong message, instant performance drop.

How do you handle the migration of custom fields and properties that brands rely on for personalization?

“Anatta maps each field to Klaviyo custom properties,” Smith shares. “Brands often forget birthday fields, preferences, and VIP flags, so we build a checklist to track them.”

“This is also a good time to peel back the layers on that data a little bit and find out where the gaps are, if there are any,” Leeth recommends. “The last thing you want is to find inconsistencies with formatting or how that data has come into the platform over the history of that data.”

Brands often forget birthday fields, preferences, and VIP flags, so we built a checklist to track them.

BFCM-specific concerns

What’s your testing protocol before going live with Klaviyo, especially for BFCM-critical functionality?

Smith details Anatta’s testing protocol, which validates the following:

• Form behaviors
• Flow triggers and logic
• Segment accuracy
• Email rendering across multiple clients
• Deliverability using seed lists

“This ensures complete readiness and reliability for BFCM,” Smith says.

Campbell recommends running a full in depth audit of the account before starting a migration “Have someone check existing automations, segments and integrations” he says. “It can even be worth finding a virtual assistant who might be more affordable. Give them a list of tasks to run through and test and map all aspects of your program.”

What monitoring do you put in place immediately after migration to catch any issues before they impact BFCM performance?

“Anatta establishes live dashboards, monitoring key metrics such as flow revenue, email deliverability, unsubscribe rates, and error logs,” Smith says. “This proactive monitoring continues closely for two weeks post-launch to swiftly address any issues.”

How do you validate that all automations are firing correctly after migration?

At Anatta, the team “validates automations using dedicated test accounts to simulate real-world triggers,” Smith says. “Klaviyo’s built-in flow analytics confirm all elements—including sends, delays, and conditional splits—function precisely as intended.”

Will Klaviyo be able to handle BFCM email volume?

“Yes, Klaviyo is specifically designed to handle high-volume email campaigns,” Smith says. “However, optimal deliverability requires strategic domain warming and precise segmentation of engaged contacts, which Anatta prepares weeks in advance of BFCM.”

What if something goes wrong during BFCM?

Smith explains Anatta’s contingency approach: “Anatta sets fallbacks (backup flows), maintains parity with the old ESP for a few weeks, and keeps Klaviyo’s support contacts preloaded.”

Can we schedule our BFCM campaigns in advance?

“Absolutely,” Smith confirms. “Klaviyo offers advanced scheduling capabilities, allowing you to precisely plan and A/B test your campaigns ahead of time. We recommend finalizing and scheduling BFCM campaigns at least 1–2 weeks in advance to ensure smooth execution.”

Support and resources

What support is available during migration?

“We’re always there for questions and walking brands through some of the things that they’re unsure about as they get their hands dirty on the new platform,” says Leeth.

“Even with the best help community, brands need things curated for them,” Santorineos agrees. “One of the nice things about working with an agency partner is that we can help curate that for them.”

“We have bookmarks for days,” adds Leeth.

Even with the best help community, brands need things curated for them. We do that curating.

How do we train our team on Klaviyo?

Smith cites several training options for team members:

• Live training
• Custom documentation
• Recorded walkthroughs
• Access to Klaviyo Academy

What if we need help after migration?

“Anatta offers post-launch support and check-ins, especially through BFCM,” Smith explains. “Ongoing optimization is often needed for flows and segmentation.”

Post-migration optimization

How quickly can we expect to see results?

“Initial improvements typically appear within 1–2 weeks, particularly for high-impact flows like abandoned cart and welcome series,” Smith says. “However, comprehensive performance enhancements fully ramp up within 30–60 days after migration.”

What Klaviyo features should we explore after BFCM?

Smith recommends exploring:

• Predictive analytics
• Multi-touch attribution
• SMS
• Custom events from Shopify
• Product recommendations via catalog sync
• Klaviyo Data Platform features

How do we measure migration success?

At Anatta, Smith defines migration success by:

• Uninterrupted service
• Improved revenue from automated email flows
• Enhanced deliverability
• Stronger segmentation performance
• More efficient campaign execution post-migration

“It all comes down to sales,” says Leeth.

Considering migrating to Klaviyo?

Read success stories from brands who made the switch.

Read now

Lessons learned

What’s the biggest migration mistake you’ve seen that impacted a brand’s BFCM performance?

“The most critical mistakes are neglecting email domain warm-up and failing to migrate suppression lists,” says Smith. “These errors severely impact email deliverability, subscriber trust, and BFCM revenue performance.”

“We’re careful to not move the same problems over,” says Campbell.

Looking back at successful pre-BFCM migrations, what common factors contributed to their success?

“Successful migrations typically start early, involve a dedicated email manager, clearly defined project plans, strong stakeholder buy-in, thorough QA testing, and established fallback contingency plans,” Smith explains.

Successful migrations typically involve a dedicated email manager, clearly defined project goals, and thorough QA testing.

Ready to make the switch?

Migrating to Klaviyo before BFCM can be transformative for your business, but success depends on careful planning and expert execution.

As the only CRM designed exclusively for B2C businesses, Klaviyo provides the advanced segmentation, automation, and analytics capabilities you need to maximize your holiday performance—as long as you migrate with the right strategy and timeline.

Remember: start early, plan thoroughly, and don’t hesitate to work with experienced migration partners that can make your transition seamless and your BFCM results stronger than ever.