klaviyo-migration-deep-dive

# Klaviyo Migration Deep Dive ## Overview Comprehensive guide for migrating to Klaviyo from legacy APIs (v1/v2), competing ESPs (Mailchimp, SendGrid, etc.), or re-platforming with the strangler fig pattern. Covers data migration, API mapping, and validation. ## Prerequisites - Target Klaviyo account configured - `klaviyo-api` SDK installed - Source system access for data export - Feature flag infrastructure (for gradual rollout) ## Migration Types | Migration | Complexity | Duration | Risk | |-----------|-----------|----------|------| | Klaviyo v1/v2 to current API | Low-Medium | 1-2 weeks | Low | | Mailchimp/SendGrid to Klaviyo | Medium | 2-4 weeks | Medium | | Custom ESP to Klaviyo | High | 4-8 weeks | High | | Full re-platform | High | 2-3 months | High | ## Instructions ### Step 1: Legacy v1/v2 to Current API The most common migration. Klaviyo deprecated v1/v2 endpoints in favor of the JSON:API REST API. ```typescript // ============================================================ // BEFORE: Legacy v1/v2 endpoints (DEPRECATED, will stop working) // ============================================================ // v1 Track (event tracking) // POST https://a.klaviyo.com/api/track // Body: { token: "PUBLIC_KEY", event: "Placed Order", ... } // v2 List Subscribe // POST https://a.klaviyo.com/api/v2/list/LIST_ID/subscribe // Headers: { api-key: "pk_***" } // v1 Identify (profile creation) // POST https://a.klaviyo.com/api/identify // Body: { token: "PUBLIC_KEY", pro...