ESP Migration

Your migration partner — from platform choice to cutover.

We're agency partners on Klaviyo, Customer.io, HubSpot, Braze, and more — with 20+ migrations completed. Still evaluating, about to sign, or already mid-cutover: we bring the platform depth and hands-on execution so revenue stays intact through the move.

Book a migration consult See where you fit

Where you are in the process

Three stages — and the earlier we talk, the better.

The ideal time is before you sign. We can help you choose the right platform, plan migration scope, and align your team before contracts lock in terms and timing.

Still decidingIdeal timing

Exploring which ESP is right

You're evaluating platforms — comparing options, weighing integrations, or deciding whether to stay put. This is the best time to talk. We'll assess your stack, volume, and goals and recommend what fits before anyone signs a contract.

Book a platform evaluation

Pre-contractIdeal timing

Platform chosen, not signed yet

You've narrowed it down to your next ESP — but the contract isn't executed yet. Talk to us before you sign. We can align on migration scope, timeline, and technical requirements so the deal and the cutover plan match.

Talk before you sign

Post-contract

Signed and ready to migrate

Your new ESP contract is in place and you need execution — data migration, flow rebuilds, SMS transition, event reconnects, and peak-season-safe cutover planning. We run the migration and most clients continue on a retention retainer once live.

Plan your migration

The Problem

Replatforming is high-stakes — and most teams only get one shot.

The brands that come to us aren't setting up email for the first time. They're outgrowing a legacy ESP, consolidating SMS, or switching after an agency relationship that plateaued — and they need the move done right.

Choosing the wrong platform

Signing with an ESP that doesn't fit your data model, volume, or integrations — then paying for a migration 18 months later.

Migration fear keeps you stuck

You know you've outgrown your current ESP, but the risk of revenue loss, broken flows, and deliverability damage has delayed the move for years.

Data and events don't reconnect

Lists move over, but purchase events, custom properties, and integrations stay broken — so flows and segments underperform from day one on the new platform.

SMS is a separate project

Moving email is hard enough. Adding an SMS replatform — short-code approvals, consent records, and cross-platform transitions — multiplies complexity fast.

Case Study

Enterprise-scale migration — live before peak season ended.

A leading national pet subscription brand (name withheld) engaged us for a full email and SMS replatform — completed in under three months during Q4 with minimal disruption.

10M

Active profiles migrated

25M

Total contact records

<3 mo

Full cutover timeline

Q4 peak

Completed during holiday season

The program wasn't small — millions of active subscribers, deep flow architecture, and SMS on a separate platform. We migrated email from a legacy ESP and consolidated SMS onto the same stack, navigating short-code approval and consent transfer along the way. Data and engineering teams were in the room throughout: reconnecting purchase events, behavioral triggers, and the custom data points the automation stack depended on.

The cutover landed during the highest-volume quarter of the year. Deliverability held. Revenue variance stayed controlled. That's the bar we plan for — not a quiet off-season switch, but a migration that survives real send volume.

What we migrated

Email replatform from a legacy ESP — full list, segment, and flow migration to the new platform
SMS transition from a dedicated SMS provider, including guided short-code approval and consent continuity
Cross-functional work with data and engineering teams to reconnect key events, custom properties, and integration touchpoints
Parallel-run discipline and phased cutover so sends continued through peak season with stable deliverability

How we migrate

Six phases. Built for complexity.

Every migration follows the same discipline — whether you're moving 50,000 contacts or 10 million.

Audit & platform fit

Map your current ESP, flows, segments, integrations, SMS setup, and revenue dependencies. If you're still deciding, we recommend the platform that fits your data model, volume, and stack — not a one-size-fits-all default.

Data migration planning

Subscriber lists, consent records, custom properties, engagement history, and segment logic — scoped and validated before anything moves.

Flow & template rebuild

Every automation reconstructed on the new platform using native capabilities — not a one-to-one copy of what was broken on the old one.

Events & integrations

Work alongside your data and engineering teams to reconnect purchase events, behavioral triggers, and third-party integrations so segments and flows actually fire.

SMS & deliverability

Short-code approvals, SMS consent transfer, IP/domain warm-up, and parallel-send validation — especially critical when email and SMS move together.

Cutover & stabilization

Phased cutover with real-time monitoring, post-migration audits, and a stabilization window — planned around your calendar, including peak season if that's the reality.

Who This Is For

Brands replatforming — not starting from scratch.

Click a scenario that sounds like you to see how we'd approach it.

Track Record

Migrations at every scale.

20+

ESP migrations completed

Across Klaviyo, Customer.io, HubSpot, Braze, SFMC, and legacy ESP cutovers — from mid-market to enterprise list sizes.

<5%

Typical revenue variance

Parallel sends and phased cutover keep most programs within a low single-digit percent of normal during transition.

28 days

Average mid-market timeline

Smaller programs often stabilize within four weeks. Enterprise-scale moves — 10-million-profile lists and dual-channel cutovers — run longer with staged migration.

10+

Years migration experience

Deep ESP expertise across platforms — not a generalist agency learning your stack on your dime during the highest-stakes project you'll run.

FAQ

Common questions.

Before you sign with your next ESP — ideally while you're still comparing platforms. We can help you evaluate options, pressure-test vendor proposals, and structure the migration plan before terms are locked. If you've already signed, we can still execute — but the pre-contract window is where we add the most strategic value.

We work across Klaviyo, Customer.io, HubSpot, Braze, Salesforce Marketing Cloud, and others — plus cutovers from legacy ESPs. We'll recommend the platform that fits your business, data model, and integrations. For many eCommerce brands on Shopify that points to a specific choice, but the recommendation always follows the assessment.

Mid-market programs often complete in 3–5 weeks. Enterprise-scale migrations — large lists, dual email-and-SMS moves, complex event reconnects — can run 2–3 months. We've completed a 10-million-active-profile migration in under three months during Q4 peak season.

Yes — with the right plan. A recent enterprise cutover landed during Q4 with controlled revenue variance and stable deliverability. Peak season doesn't make migration easy, but it doesn't make it impossible if the phasing, parallel runs, and event reconnects are scoped correctly.

Most clients continue with us on a Retention Strategy & Execution retainer — we already know your program, flows, and data model. Migration is often the start of the relationship, not the end.