Expert Developer for Server-Side Analytics Integration Fixes and Performance Optimization

We are seeking a skilled developer to finalize and optimize an existing server-side tracking integration. The current infrastructure is operational, utilizing a serverless endpoint on Google Cloud Run, with Firestore for idempotency, signature validation, and event routing to GA4 (Measurement Protocol), Meta Conversions API, TikTok Events API, and an affiliate platform. The primary goal is to address remaining issues and ensure robust, accurate performance in production.

Scope of Work:

1.  GA4 Purchase Event Value Correction: The purchase event currently sends the list price to GA4 instead of the actual amount charged (due to discount coupons). This needs to be investigated and fixed to reflect the correct transaction value.
2.  GA4 Refund Event Integration: The refund event is not currently reaching GA4. The developer will need to investigate the cause and implement a fix to ensure these events are properly tracked.
3.  Transaction Linking for Refunds: Purchase and refund events originate from different sources and lack a common identifier. A mechanism must be created to link refunds to their original transactions in GA4, using the Stripe customer ID as the key, with persistence in Firestore.
4.  Endpoint Performance Optimization: The current endpoint response time is approximately 18 seconds. This latency needs to be investigated and significantly reduced to prevent timeouts and retries from webhook providers.
5.  Error Log Review: Review and address approximately 143 errors currently logged in Cloud Logging.

Acceptance Criteria:

Deliverables will be validated through real production data, not simulated payloads. The successful candidate will provide screenshots or links demonstrating the following in production:

*  GA4 showing both purchase and refund events, with a shared transaction_id, and values consistent with Stripe records.
*  Meta Events Manager successfully receiving the event.
*  TikTok Events Manager successfully receiving the event.
*  The corresponding Cloud Run log entry for the validated transaction.

A test coupon and address will be provided, and any associated costs for real transactions will be reimbursed. This is a fixed-scope, short-term engagement, with payment upon validated delivery.