Benjamin Casarez

Built and operated full-stack features for logistics and physical-operations products using Java, TypeScript, React, PostgreSQL, and distributed backend services, owning work from design through production monitoring. Developed APIs and event-driven workflows for real-time location, operational status, and delivery data, using idempotent processing to protect downstream state from duplicated or retried events. Improved high-traffic service paths by profiling and analyzing SQL execution plans, adding caching, and using asynchronous processing to reduce p95 latency by roughly 30% for a key operational workflow. Instrumented telemetry across request latency, failures, queue behavior, and customer workflows using production evidence to guide reliability improvements. Partnered with Product and Design to break operational problems into iterative releases based on real user behavior.

Developed backend and web capabilities for local-delivery workflows involving merchants, orders, dispatch, drivers, and customer status using Java, Spring Boot, React, and SQL-backed services. Designed REST APIs with explicit contracts, authentication, validation, pagination, and failure semantics so clients could evolve independently of backend implementations. Addressed delivery-state divergence after retries from external systems by introducing durable event identifiers and transactional idempotency rather than assuming exactly-once delivery. Participated in load testing, incident response, rollout monitoring, and post-incident reviews where latency and reliability impacted active deliveries.

Built Java/Spring Boot services and React application features supporting restaurant ordering and operational workflows, including REST integrations, relational data models, and customer-facing interfaces. Implemented asynchronous jobs and third-party integrations with retries, rate limits, and partial-failure recovery and reconciliation logic. Restored performance for a widely used API as historical data grew by using query profiling and targeted indexing without introducing a new persistence layer. Contributed to automated tests, peer reviews, CI/CD improvements, and production debugging across frontend and backend components.