Backend/Data Engineer (West Fort)

We are looking for a Backend Database Engineer to design, build, secure, and optimize the backend data architecture of a multi-tenant Shopify embedded public application. The application processes large volumes of Shopify product, variant, metafield, inventory, bulk-edit, import, export, scheduling, audit, and synchronization data. The engineer will be responsible for ensuring that the PostgreSQL database and backend services remain secure, tenant-isolated, scalable, reliable, and cost-efficient. This role requires solid expertise in PostgreSQL, Node.js, Express, Prisma ORM, database transactions, concurrency control, background-job processing, and Shopify Admin GraphQL integrations. Key Responsibilities Database Architecture Design scalable PostgreSQL schemas for a multi-tenant Shopify public application. Ensure every merchant-owned record is strictly scoped using the Shopify store identifier. Design tenant-safe primary keys, foreign keys, unique constraints, indexes, and relations. Prevent cross-store data access through internal IDs, Shopify GIDs, job IDs, relation IDs, or browser-provided identifiers. Design schemas for product mirrors, filter indexes, bulk-edit jobs, previews, snapshots, audit logs, imports, exports, subscriptions, schedules, idempotency records, and transactional outboxes. Plan data retention, archival, partitioning, cleanup, and database-growth controls. Query Performance and Optimization Analyze and optimize PostgreSQL and Prisma queries. Identify slow queries, missing indexes, sequential scans, N+1 queries, unnecessary joins, over-fetching, and inefficient pagination. Use EXPLAIN and EXPLAIN ANALYZE to diagnose query performance. Design effective composite, covering, partial, expression, GIN, and BRIN indexes where appropriate. Optimize filtering, sorting, search, counts, facets, and exports against a local Shopify product mirror. Reduce database compute usage, connection pressure, storage growth, network transfer, and Neon egress costs. Data Integrity and Concurrency Design safe transactions for multi-step backend operations. Identify and eliminate race conditions, lost updates, duplicate processing, stale writes, and time-of-check-to-time-of-use defects. Replace unsafe read-check-write operations with conditional updates, compare-and-swap logic, versioning, row locks, or database constraints. Design reliable state transitions for preview, approval, execution, cancellation, retry, verification, and undo workflows. Implement idempotency protections for HTTP requests, Shopify mutations, webhook events, queue jobs, imports, exports, and scheduled operations. Ensure database writes and queue publishing are coordinated using a transactional outbox or equivalent durable pattern. Shopify Data Synchronization Build and maintain a durable local mirror of Shopify products, variants, metafields, inventory, collections, and related data. Support initial synchronization using Shopify Bulk Operations and streamed JSONL imports. Design staging, validation, indexing, atomic activation, cleanup, and rollback workflows. Process Shopify webhooks safely and idempotently. Handle webhook duplication, delay, out-of-order delivery, deleted products, stale events, and replay attempts. Prevent deleted products or outdated records from being accidentally restored. Maintain accurate product filter indexes for fast search, filtering, preview, export, and bulk-edit target resolution. Backend Development Develop and maintain backend services using Node.js and Express. Build secure repository and service layers using Prisma ORM and PostgreSQL. Review controllers, repositories, services, workers, and scheduled jobs for database safety. Ensure the browser never supplies trusted final mutation data for bulk-edit operations. Ensure apply and undo operations load authoritative server-side snapshots and preview contracts. Implement validation, authorization, error handling, logging, and audit trails. Maintain backward compatibility while improving production reliability. Queue and Worker Reliability Design database-safe BullMQ and Redis job-processing workflows. Prevent duplicate job execution and conflicting workers. Implement retry-safe and idempotent workers. Support per-store concurrency limits, exponential backoff, dead-letter handling, stuck-job detection, and cancellation. Ensure database state remains correct when a worker crashes, retries, times out, or processes the same job more than once. Design safe recovery workflows for partially completed operations. Security and Tenant Isolation Enforce strict tenant isolation across all reads, writes, updates, deletes, joins, aggregates, counts, and background jobs. Review database access paths for authorization bypass and insecure direct-object reference risks. Prevent SQL injection and unsafe dynamic-query construction. Protect sensitive merchant and application data. Design least-privilege database .