Sebastián – React, React Native, Node.js

A leading global digital transformation services and product engineering company. It specializes in software development, enterprise platform engineering, and strategic business consulting

• Contributed to backend service design and architectural decisions across a cross-functional pod.
• Designed and implemented GraphQL and REST APIs, including schema, error contracts, and performance budgets, ensuring clean client integration across web and mobile.
• Drove technical code reviews and engineering standards, reducing regressions and improving velocity through consistent patterns and reusable modules.
• Mentored mid-level engineers on system design, TypeScript best practices, and AWS deployment patterns.

An American daily tabloid newspaper, one of the oldest continuously published newspapers in the United States. Today, it operates as a multi-platform media company spanning print, digital networks, video production, apps, and podcasts.

• Owned two production microservices end-to-end for CMS data retrieval and payload transformation, powering the mobile reading experience for iOS and Android clients at the newspaper.
• Built a transformation microservice mapping raw CMS payloads into the mobile team's predefined schema, guaranteeing contract consistency and unblocking client integration.
• Reduced response payload size by 10% after analyzing the end-to-end data flow, improving mobile latency and battery efficiency.
• Investigated and documented the company's custom CMS modules and internal packages, producing internal notes that unblocked two subsequent features.
• Operated within AWS and Docker and supported release reliability through CI/CD workflows in GitHub Actions.

A digital musculoskeletal health platform that blends in-clinic and at-home rehabilitation solutions, providing remote therapeutic monitoring, digital home exercise programs, and outcomes tracking for physical and occupational therapy organizations.

• Drove a platform-wide performance overhaul, rebuilding core services to significantly reduce end-to-end latency for patient and provider workflows in a hybrid MSK care product.
• Optimized the PDF generation service for training specifications from 6s to 2ms, eliminating a major UX bottleneck in provider workflows.
• Shipped full-stack features across the provider web in React and the patient mobile in React Native, backed by Node.js services and PostgreSQL on AWS.
• Supported reliable delivery of RTM and Home Exercise Programs, ensuring care content reached patients consistently outside the clinic.
• Enhanced remote therapeutic monitoring features, resulting in a 30% increase in patient adherence.
• Improved data processing efficiency by 40%, allowing faster insights for clinicians.
• Integrated API solutions that enabled partnerships with multiple healthcare providers, leading to a 20% growth in user adoption.

A B2B payments product tenant onboarding experience for new business tenants.

• Built and maintained the tenant onboarding experience for a B2B payments product, guiding new business tenants from setup to ready-to-transact.
• Implemented onboarding flows in React using PayPal's internal component library, ensuring consistent, accessible, and compliant UX across products.
• Developed onboarding steps for tenant creation, admin and user setup, billing configuration, and payment readiness, including verification and required info capture.
• Coordinated with backend and product teams to align onboarding UX with payment-domain requirements, including error handling, retries, and state progression.
• Optimized backend services, reducing transaction processing time by 10%.
• Collaborated with a cross-functional team in developing a microservices architecture, resulting in a 15% increase in system reliability and scalability.