Platform Migration

A platform migration is a strategic opportunity. Most brands treat it like a technical chore.

Moving to Klaviyo from another email marketing platform is one of the most consequential decisions an ecommerce brand's marketing team will make. Done properly, it is the foundation of a materially better programme — cleaner data, more powerful segmentation, tighter Shopify or WooCommerce integration, and access to the automation capabilities that drive consistent retention revenue. Done poorly, it is months of disruption, data loss, deliverability damage, and a new platform that performs no better than the one it replaced.

Most in-house migration attempts fall into the second category — not because of a lack of effort, but because a Klaviyo migration requires a specific combination of platform expertise, data management discipline, deliverability knowledge and project management rigour that most marketing teams do not have available simultaneously. The list gets migrated but the historical segment logic does not translate. The flows are rebuilt but the trigger conditions are wrong. The sending domain is configured but the authentication records are incomplete. The programme goes live, and the first batch of sends lands in the spam folder.

FlowFixer's Platform Migration project handles the entire process — from migration planning through to post-launch monitoring — with the precision and expertise that ensures your Klaviyo programme starts properly, not from a position of remediation.

What the engagement covers

Pre-migration audit and planning

Before anything is moved, we conduct a thorough audit of your current platform — reviewing your list structure, segment definitions, flow architecture, template library, historical engagement data, suppression records, consent data, and sending configuration. The purpose is not just to understand what exists, but to assess what is worth migrating directly, what should be rebuilt to a higher standard in Klaviyo, and what should be left behind entirely. Many migration engagements surface years of accumulated platform debt — inactive segments, broken flows, inconsistent consent records — that should be resolved rather than replicated.

Migration architecture design

We design the Klaviyo account architecture before migrating a single contact — list structure, segment framework, property naming conventions, custom property definitions, and the integration configuration for your Shopify or WooCommerce store. Starting with a well-designed account architecture ensures that the data being migrated lands in a structure that supports your programme's requirements, rather than being forced into whatever structure was most convenient to migrate from.

Data migration and validation

The full migration of your subscriber data — contact records, custom properties, historical engagement data, purchase history, suppression lists and consent records — with validation at every stage to ensure data integrity. We do not consider a data migration complete until we have verified that the data in Klaviyo accurately reflects what was in the source platform, that consent records are correctly mapped, that suppressions are in place, and that historical purchase data is correctly associated with subscriber profiles.

Flow rebuild in Klaviyo

Your existing automation flows are not simply copied across — they are rebuilt in Klaviyo with the logic, features and capabilities that the platform natively supports. Where your previous platform required workarounds or third-party integrations to achieve automation functionality that Klaviyo handles natively, we remove those dependencies and build the flows properly. Where flows were underperforming on your previous platform, we rebuild them to a higher standard rather than replicating what was not working.

Template migration and rebuild

Email templates from your previous platform are assessed and either migrated, adapted or rebuilt in Klaviyo depending on their quality and the degree to which they can be translated without quality loss. For brands using the migration as an opportunity to upgrade their visual identity in email, we can scope a concurrent template design project that ensures you launch on Klaviyo with a properly branded design system rather than a migrated version of what you had before.

Klaviyo integration with Shopify or WooCommerce

A correctly configured Klaviyo integration with your ecommerce platform is the foundation of everything that makes Klaviyo more powerful than a generic email tool — dynamic product content in flows, purchase-based segmentation, browse and cart abandonment triggers, predictive LTV data, and the real-time behavioural data that enables genuine personalisation. We configure the integration to the full extent of what Klaviyo natively supports, validate that data is flowing correctly in both directions, and test every trigger and data point that your flows depend on before going live.

Sending domain configuration and warm-up

Launching on a new sending domain — or moving sending volume from one platform to another — requires a structured approach to deliverability that most brands overlook entirely. We configure your Klaviyo sending domain with correct SPF, DKIM and DMARC authentication, build a warm-up plan appropriate to your sending volume and list engagement profile, and monitor inbox placement rates throughout the launch period to catch and resolve any deliverability issues before they compound.

Cutover planning and execution

The migration cutover — the point at which your programme moves from the old platform to Klaviyo — is the highest-risk moment of any migration project. We plan and execute it with a structured cutover sequence that maintains automation continuity throughout: your Klaviyo flows go live and are verified before the equivalent flows on the old platform are deactivated, so there is no window during which subscribers fall through the gap between two programmes.

Post-migration monitoring

After cutover, we monitor your programme's performance through the first four weeks on Klaviyo — tracking deliverability metrics, flow performance, data integrity and integration health — and resolve any issues that emerge before handing full ownership of the programme to your team.

Platforms we migrate from

We have migrated brands to Klaviyo from Mailchimp, Omnisend, Dotdigital, Salesforce Marketing Cloud, HubSpot, Braze, Iterable, ActiveCampaign, Drip and several custom or proprietary platforms. If you are on a platform not listed here, we will assess feasibility and complexity during the initial scoping call.

Frequently asked questions

Will our automation flows keep running during the migration?

Yes. Maintaining automation continuity throughout the migration is one of the core disciplines of our migration process. We build and verify your Klaviyo flows before deactivating the equivalent flows on your current platform — so there is no period during which a subscriber entering your welcome flow, your abandoned cart sequence or your post-purchase programme fails to receive the emails they should. The cutover sequence is planned explicitly to prevent gaps and we monitor it in real time during execution.

How long does a typical migration take?

Migration timeline depends on programme complexity — the size of your list, the number of flows, the volume of historical data, and the degree to which your current platform's data structures translate cleanly to Klaviyo's. A straightforward migration for a brand with a well-maintained list and a small number of flows can be completed in two to three weeks. A complex migration from a legacy enterprise platform with significant historical data, multiple regional programmes and a large flow library may take six to eight weeks. We provide a specific timeline estimate during the scoping call once we have reviewed your current platform.

Should we use the migration as an opportunity to upgrade our programme or just replicate what we have?

Both approaches are valid and we discuss this explicitly during scoping. Replicating what you have gets you onto Klaviyo faster and with lower project risk — and if your current programme is performing well, that is a reasonable choice. Using the migration as an upgrade opportunity takes longer but means you launch on Klaviyo with a better programme than you had before, rather than the same programme on a new platform. Many brands choose a hybrid approach — migrate the core infrastructure cleanly and quickly, then invest in programme improvements on the new platform over the following months, either through a subsequent project or a FlowFixer subscription.