Shopify → Klaviyo Integration Engineer — Custom Multi-Account Sync (Contract)

We run a single Shopify Plus store serving 7 European markets (NL, DE, FR, ES, IT, UK, SE). We want to sync data from this one store into 7 separate Klaviyo accounts (one per market), and we need someone who can first figure out the right way to do this, then build it. The native Shopify–Klaviyo integration is 1:1, so this requires a custom solution that routes events from one store to the correct Klaviyo account based on market. We're looking for an engineer who can scope it properly, recommend the best approach, and deliver a reliable, documented integration. Phase 1 — Discovery (paid, small) Assess feasibility and design the architecture for fanning out 1 Shopify store to 7 Klaviyo accounts Advise on the best approach: custom code vs an automation platform (Make / n8n) vs hybrid Pressure-test whether 7 separate accounts is even the right call, or whether 1 account with per-market segmentation and separate sending domains achieves the same goal Deliver a clear plan: approach, effort, cost, risks, and what data flows where Phase 2 — Build (if we proceed) Build the integration: route Shopify events (orders, customers, checkouts, fulfillments) to the correct Klaviyo account by market / country / language Handle historical backfill plus ongoing real-time sync Manage consent / GDPR correctly across all accounts (EU) Add error handling, retries, deduplication, logging, and monitoring so it doesn't silently break Document everything so it's maintainable by our team afterwards You're a strong fit if you Have built custom Shopify integrations using webhooks and the Admin API Know the Klaviyo API well, including working across multiple accounts and pushing profiles / events / consent Can design routing logic that maps orders and customers to the right destination reliably Are comfortable with Make / n8n and/or custom code (Node / Python) and can advise which fits best Think about edge cases: duplicates, failures, backfill, data consistency Nice to have Shopify Plus and multi-market / multi-locale experience Experience with deliverability and multi-domain sending setups To apply Briefly describe how you'd approach syncing one Shopify store to multiple Klaviyo accounts, or point us to a similar multi-destination / multi-account sync you've built. What went wrong the last time you built something like this, and how did you handle it? Applications without a specific technical answer won't be reviewed.