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Hi, I’m David Santos—a senior full-stack engineer with 10 years of experience building Node.js and React SaaS platforms across fintech, workforce, healthcare, and e-commerce. I design multi-tenant architectures, implement async job processing, and integrate third-party APIs to deliver scalable products. I actively explore AI-augmented development with Claude Code, Cursor, and Copilot, and I’ve shipped dashboards and features with real-time data streaming, secure OAuth2 flows, and resilient event-driven workflows. I enjoy mentoring teammates, collaborating with product managers, and delivering high-performance, reliable software.…Hi, I’m David Santos—a senior full-stack engineer with 10 years of experience building Node.js and React SaaS platforms across fintech, workforce, healthcare, and e-commerce. I design multi-tenant architectures, implement async job processing, and integrate third-party APIs to deliver scalable products. I actively explore AI-augmented development with Claude Code, Cursor, and Copilot, and I’ve shipped dashboards and features with real-time data streaming, secure OAuth2 flows, and resilient event-driven workflows. I enjoy mentoring teammates, collaborating with product managers, and delivering high-performance, reliable software.

David Santos

Full Stack Developer, Web Developer, Back-End Developer, +2

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Hi, I’m David Santos—a senior full-stack engineer with 10 years of experience building Node.js and React SaaS platforms across fintech, workforce, healthcare, and e-commerce. I design multi-tenant architectures, implement async job processing, and integrate third-party APIs to deliver scalable products. I actively explore AI-augmented development with Claude Code, Cursor, and Copilot, and I’ve shipped dashboards and features with real-time data streaming, secure OAuth2 flows, and resilient event-driven workflows. I enjoy mentoring teammates, collaborating with product managers, and delivering high-performance, reliable software.…Hi, I’m David Santos—a senior full-stack engineer with 10 years of experience building Node.js and React SaaS platforms across fintech, workforce, healthcare, and e-commerce. I design multi-tenant architectures, implement async job processing, and integrate third-party APIs to deliver scalable products. I actively explore AI-augmented development with Claude Code, Cursor, and Copilot, and I’ve shipped dashboards and features with real-time data streaming, secure OAuth2 flows, and resilient event-driven workflows. I enjoy mentoring teammates, collaborating with product managers, and delivering high-performance, reliable software.

Available to hire

Hi, I’m David Santos—a senior full-stack engineer with 10 years of experience building Node.js and React SaaS platforms across fintech, workforce, healthcare, and e-commerce. I design multi-tenant architectures, implement async job processing, and integrate third-party APIs to deliver scalable products.

I actively explore AI-augmented development with Claude Code, Cursor, and Copilot, and I’ve shipped dashboards and features with real-time data streaming, secure OAuth2 flows, and resilient event-driven workflows. I enjoy mentoring teammates, collaborating with product managers, and delivering high-performance, reliable software.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Lead / Senior Full Stack Engineer at WillowTree (TELUS Digital)

March 1, 2023 - January 1, 2026

Designed and shipped a multi-tenant SaaS backend with NestJS, Prisma, and PostgreSQL, implementing workspace isolation, row-level security, tiered subscription logic, and Stripe billing with webhook-driven lifecycle handling. Built BullMQ-powered async pipelines for scheduled report generation, webhook retries, and third-party data sync tasks, with dead-letter queues and retry backoff strategies. Architected event-driven microservices using AWS SQS/SNS to decouple workflows and maintain resilience under spikes. Integrated OpenAI and Anthropic APIs into production services, building Python-based RAG pipelines with pgvector embeddings and prompt chains; introduced Redis-based response caching to reduce inference costs by 35%. Delivered an AI-driven financial insights dashboard using Next.js App Router, TypeScript, and TailwindCSS with real-time streaming via WebSockets and Server-Sent Events. Implemented OAuth2 and OpenID Connect flows for third-party integrations, managing token refresh

Senior Full Stack Engineer at Infinum

March 1, 2020 - March 1, 2023

Built a zero-to-one patient management SaaS platform, multi-tenant data architecture with row-level security, tenant-scoped API middleware, and dynamic schema routing for isolated environments. Implemented granular RBAC with OAuth2 and audits; integrated EHR and FHIR-compliant APIs with retries and circuit breakers. Optimized PostgreSQL queries, used Redis caching to reduce latency, and eliminated N+1 patterns. Implemented event-driven ingestion via Redis Pub/Sub and AWS Lambda to decouple ingestion from UI rendering for 10x spikes. Built real-time exam scheduling with Next.js, WebSockets, and Mapbox for 3,000 concurrent sessions across 45 locations. Created a shared component library with Storybook and Zod validation; implemented integration and E2E tests with Cypress/Jest. Adopted Python NLP pipelines via FastAPI to parse unstructured medical notes for dashboards. Led architecture reviews and pair programming to improve error handling, API contracts, and migrations. Hardened security

Senior Software Engineer at Q Agency

January 1, 2017 - February 1, 2020

Architected and launched a travel booking SaaS platform with SSR/CSR architecture handling 1M monthly visitors; built dynamic pricing engine with Node.js and Redis for real-time inventory and time-decay rules, increasing conversions. Implemented subscription management with Stripe; defined REST and GraphQL APIs for multi-tenant product; added API versioning, Redis rate-limiting, Joi validation, and auto-generated OpenAPI docs. Established Docker-based dev/staging with Azure DevOps pipelines; standardized parity and onboarding. Implemented observability with Sentry and Prometheus/Grafana; automated end-to-end flows with Cypress/Selenium; migrated legacy codebases to TypeScript. Ensured GDPR compliance with consent management, data retention, anonymization utilities, and audit trails; collaborated with founders to translate ideas into specs and phased delivery.

Junior Software Engineer at Infobip

September 1, 2014 - December 1, 2016

Gained foundational full-stack experience across Node.js, Python, PHP and databases; integrated Kafka and Redis pipelines for multi-channel campaigns; authored REST APIs with Express and JWT, later migrating high-traffic endpoints to GraphQL. Built real-time dashboards with Socket.io and Chart.js; wrote Python automation scripts to reduce manual tasks. Supported hybrid cloud migration to AWS; participated in on-call incident response for messaging services.