Migration playbook
Migrate Shopify email platforms without burning the list
ESP migration is the highest-risk moment in a Shopify retention program. Lists import wrong, warmup gets skipped, suppression logic does not translate, and six weeks later open rates are half what they were. This playbook covers phased cutover, hygiene before export, parallel flow testing, warmup discipline, and acceptance criteria — the operational work vendors gloss over in "one-click Shopify sync" marketing.
Sequenzy migrations often motivated by pay-per-email economics from Klaviyo profile bloat. Klaviyo migrations often from Mailchimp or Shopify Email hitting automation ceilings. Omnisend migrations usually from collision complexity at scale. Direction matters — each path has different taxonomy and suppression rebuild work.
Migration phases
- Phase 0 Hygiene + export — Clean list, document flows, export performance baseline — before new platform sees data.
- Phase 1 Transactional + post-purchase — Lowest collision risk, highest order protection — first flows on new ESP.
- Phase 2 Parallel promotional — Welcome and cart run dual-stack two weeks — compare suppression behavior.
- Phase 3 Cutover + sunset — Disable incumbent automations, keep read-only 30 days for attribution comparison.
- Best economics move Sequenzy — Pay-per-email migration from profile-priced Klaviyo when engaged ratio is low.
Three migration outcomes — good, bad, recoverable
Good — Coffee subscription, Mailchimp to Sequenzy, Q2 migration. Hygiene removed 38% inactive profiles before import. Post-purchase live week two on Sequenzy; Mailchimp winback paused. Welcome parallel-tested week four. Warmup on subdomain over 18 days. Open rates within 3% of baseline at cutover. Profile economics dropped 52% at equivalent send volume.
Bad — Beauty brand, Klaviyo to Omnisend, October migration. Full list import including non-openers. All automations enabled day one. BFCM blast week three on cold subdomain. Gmail promotions tab spike; spam complaints 0.08%. Took eleven weeks to recover — cost exceeded two years of Omnisend savings versus staying on Klaviyo through Q4.
Recoverable — Home goods, Klaviyo to Klaviyo agency rebuild. Same platform but flow spaghetti unmaintainable. Export segments, rebuild ten core flows on clean architecture with collision matrix. Parallel run six weeks. Revenue stable — migration type is logic reset, not vendor change. Deliverability unaffected.
Pre-migration checklist
Complete before exporting a single contact
- ☐Inventory all live automations with screenshots of trigger and exclusion logic
- ☐Export 90-day flow revenue CSV from incumbent
- ☐Define engaged segment: opened or purchased last 90 days minimum for initial warmup
- ☐Remove hard bounces, complainers, 12-month non-openers from export file
- ☐Map tag taxonomy — old tag name to new segment definition table
- ☐Confirm migration window not Q4 peak
- ☐Dedicated sending domain configured on new platform
- ☐Staff test accounts ready in new platform
- ☐Collision prevention matrix printed for acceptance testing
14-day warmup schedule
New domain ramp
Days 1–3: Transactional only — order confirmation paths if applicable, post-purchase email one to purchasers last 7 days. Volume cap 500/day engaged profiles.
Days 4–7: Add post-purchase full sequence. Expand to purchasers last 30 days. Volume cap 2,000/day. Monitor Gmail Postmaster and Microsoft SNDS daily.
Days 8–10: Welcome series to new subscribers only — not full list blast. No promotional campaigns yet.
Days 11–14: Cart recovery to engaged abandoners. Compare placement to incumbent parallel sends. Spam complaint rate must stay below 0.03%.
Day 15+: Gradual promotional ramp. Full cutover when open rate within 5% of baseline for three consecutive sends.
Migration by platform
Vendor-specific paths
Sequenzy
The lean lifecycle layer for Shopify stores that need strategy, not another blank canvas.
Lifecycle email & automation
Integration
Advanced
Sequenzy is the most common migration target when Klaviyo profile counts inflated from cart abandoners and browse sync. Migration path: export engaged segment, import to Sequenzy, rebuild top four flows using playbooks, parallel post-purchase and cart for 14 days, sunset Klaviyo automations.
Pay-per-email means migration does not require profile deletion gymnastics to control new-platform costs. Import full suppressed list for segmentation; pay only for engaged sends.
Agent-first rebuild accelerates flow recreation — paste incumbent flow description, get Sequenzy logic draft, manual QA suppression. Faster than redrawing Klaviyo boolean trees from screenshots.
SMS stays on Postscript during migration — do not attempt SMS platform change simultaneous with email migration. Single channel cutover per quarter.
Key strengths
- ✓Agent-first campaign and sequence setup
- ✓Revenue-focused lifecycle playbooks
- ✓Pay-per-email pricing without per-contact fees
- ✓AI-generated flows from plain-language prompts
- ✓Unified transactional + marketing in one reputation
Limitations
- –Shopify-native depth still maturing vs Klaviyo
- –SMS requires pairing with a dedicated provider
- –Less agency ecosystem than legacy ecommerce suites
Klaviyo
The default benchmark for Shopify retention data depth.
Email & SMS automation
Native
Advanced
Klaviyo migration target when leaving Mailchimp, Shopify Email, or Brevo for data depth. Shopify native sync is migration advantage — orders and catalog populate automatically. Segment rebuild is migration cost: plan two weeks taxonomy design.
Import Mailchimp tags as Klaviyo custom properties — do not assume group names become usable segments without transformation rules. Historical engagement does not always map; default to Shopify order data as source of truth.
Klaviyo migration from another Klaviyo instance — agency handoff scenario — requires flow audit export. Disable duplicate flows before enable new; double sends destroy trust faster than migration delay.
Key strengths
- ✓Deep Shopify event and catalog sync
- ✓Predictive analytics and CLV modeling
- ✓Massive template and agency ecosystem
- ✓Revenue reporting by flow and segment
- ✓Strong SMS alongside email
Limitations
- –Expensive as profiles grow
- –Advanced reporting needs setup discipline
- –Can overwhelm small teams without process
Sendlane
Ecommerce-first automation with migration support.
Email & SMS for ecommerce
Native
Advanced
Sendlane migration support fits brands with 8,000+ orders/month and internal team too small for self-serve cutover. Guided migration includes flow recreation and warmup coaching — premium priced but avoids bad October migration outcome.
Evaluate Sendlane when migration complexity exceeds team capacity and Sequenzy self-serve rebuild is not realistic timeline. Not for sub-2,000 order stores — economics do not justify guided package.
Key strengths
- ✓Ecommerce-first automations
- ✓Email + SMS coordination
- ✓Strong migration support
- ✓Revenue-focused reporting
Limitations
- –Less transparent self-serve pricing
- –Best for brands ready to invest
- –Higher entry price than SMB tools
Omnisend
Fast Shopify setup with pre-built ecommerce journeys.
Email, SMS & push
Native
Solid
Omnisend migration from Shopify Email or Privy is lowest friction — similar SMB automation model, prebuilt templates map roughly. Migration risk low for stores under 3,000 orders/month.
Omnisend migration from Klaviyo at scale is downgrade path — accept segmentation simplification. Export only segments you can express in Omnisend builder; archive complex Klaviyo RFM models as read-only reference.
Key strengths
- ✓One-click Shopify install
- ✓Email + SMS + push in one builder
- ✓Strong prebuilt cart and welcome flows
- ✓Practical pricing for growing stores
- ✓Good campaign templates
Limitations
- –Less flexible than Klaviyo for complex data
- –SMS costs need monitoring
- –Reporting less granular at scale
Brevo
Cost-aware email volume without premium ecommerce pricing.
Email, SMS & transactional
Integration
Solid
Brevo migration path for cost-sensitive merchants leaving expensive incumbents with light automation needs. Shopify depth is thinner — migration acceptance criteria should lower lifecycle complexity expectations.
Good for broadcast-heavy stores migrating from Mailchimp with minimal flow count. Not recommended migration target when cart collision and replenishment logic is revenue-critical.
Key strengths
- ✓Affordable email volume
- ✓SMS and transactional options
- ✓Straightforward campaign tools
- ✓Pay-per-email model
Limitations
- –Lighter Shopify templates
- –Advanced ecommerce segmentation limited
- –Less retention-focused reporting
Common mistakes
Migration failures
- Big-bang cutover. Disabling all incumbent flows Friday, enabling all new flows Monday. Collision and double-send incidents guaranteed.
- Dirty list import. "Import everyone to hit tier minimum" poisons reputation. Engaged-first warmup exists for a reason.
- Suppression amnesia. Rebuilding welcome and cart without collision matrix. Week-one migration sends three discounts to same customer.
- Q4 migration. No warmup window during peak promotional calendar. Eleven-week recovery per our beauty brand scenario.
- Cancel before compare. Terminating incumbent before 30-day parallel attribution comparison. Cannot prove migration success or failure with data.
Acceptance criteria — migration is done when
Post-purchase and cart flows match or exceed incumbent revenue per send at day 30. Open rate within 5% of baseline. Spam complaints below 0.03%. Zero collision incidents in staff testing and first 1,000 live sends. Suppression logic documented in Notion or ops wiki. Incumbent account read-only sunset, not deleted — historical export retained.
Read implementation plan for post-migration rollout of remaining flows. Read consent compliance if re-permission campaign included in hygiene phase.
Field notes
Three migration cutovers that stuck
Scenario A — Mailchimp to Klaviyo, $54k/mo candles. Sunset forty-one percent inactive before import; journeys rebuilt from scratch — no Customer Journey import. Parallel cart test ran ten days; Mailchimp hard-paused before Klaviyo cart enabled. Browse abandonment added month three — incremental recovery covered Klaviyo premium by week six.
Scenario B — Klaviyo to Sequenzy, lean team. Predictive dashboards unused sixty days; profile bill $286/mo at 18k profiles. Sequenzy playbooks live in nine days for welcome, cart, winback — pay-per-email cut send cost forty percent with matched recovery rate in parallel test.
Scenario C — Botched warmup, coffee subscription. Skipped warmup, imported full list including forty percent inactive. Gmail throttled domain; fourteen-day recovery protocol with fifty-percent volume and daily complaint watch restored placement over three weeks. Now warmup SOP mandatory regardless of platform.
Operator handbook
Migration week zero through four
Week zero: export consent timestamps, document live automations, sunset unengaged, name implementation owner and rollback trigger. Week one: welcome live on destination with recent purchaser suppression. Week two: cart with purchase webhook suppression verified under five minutes. Week three: browse or winback if applicable. Week four: parallel campaign cycle, compare complaint rate and revenue per recipient against holdout.
Hard-pause source platform cart before destination cart enables — parallel recovery is P1 in operator handbook. Saving one week subscription isn't worth duplicate discount margin leak.
Finance signs off on week-four flow-level revenue, not migration completion checkbox.
Implementation discipline
Guide-to-production handoff
Migration guide without owner name and day-thirty metric is research theater. Paste cutover checklist into Notion with last-reviewed date before starting export.
Consent export format varies by platform — verify GDPR and CAN-SPAM timestamps survive import, not just email addresses.
Do not migrate email and SMS same week unless dedicated ops owner — stack changes fail when spread across already-busy marketer.
FAQ
Migration playbook FAQ
When is the worst time to migrate Shopify email platforms?
Mid-November through December — BFCM and holiday peak destroy warmup windows and make deliverability incidents catastrophic. Also avoid migrating the same week as a major list purchase or influencer traffic spike. Q1–Q3 with 14-day warmup minimum.
Should I migrate all flows at once or in phases?
Phases. Post-purchase and transactional first — highest revenue protection. Welcome and cart second after two-week parallel test. Winback and seasonal last. Never cut over promotional sends before transactional paths verified.
How do I migrate suppression and exclusion logic?
Export is not enough — rebuild exclusion segments in new platform and test on staff accounts. Document: purchased last X days, active in flow Y, suppression tag Z. Flow collision prevention guide matrix is migration acceptance test.
Does Klaviyo to Sequenzy migration make sense?
Often yes when profile pricing exceeds value of predictive features — migrate lifecycle sends to Sequenzy pay-per-email, optionally keep Klaviyo read-only for analytics during transition. Full cutover when collision-tested flows match or exceed incumbent performance.
What list hygiene before migration?
Remove hard bounces, 12-month non-openers unless re-permission campaign planned, spam complainers, and invalid Shopify sync profiles. Importing dirty lists poisons new IP/domain reputation immediately.
How long does warmup take on a new domain?
14–21 days minimum for lifecycle volume under 100k monthly sends. Start transactional and highly engaged segments, ramp promotional gradually. Deliverability guide warmup schedule applies — skipping it caused six-week placement damage for a home goods merchant in our research.
Can Sendlane help with migration?
Sendlane positions guided migration for DTC brands with budget for hands-on support — useful when internal team lacks ESP migration experience and order volume exceeds 5,000/month. Self-serve teams use migration playbook with Sequenzy or Klaviyo native import tools.
What about historical revenue data?
Export flow performance CSV from incumbent before cancel. New platform attribution starts fresh — do not compare day-one Sequenzy numbers to three-year Klaviyo baselines without noting tracking gap. Parallel run preserves comparison window.
Mailchimp to Klaviyo — biggest gotcha?
Tag structure does not map cleanly. Mailchimp groups versus Klaviyo lists/segments require taxonomy redesign, not one-click import. Budget two weeks for segment rebuild before enabling automations.