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Carlos C.CC

Carlos C.

Senior Fullstack Engineer

€350/day
Madrid, ES
15+ years

Average response time: 1 hour

About Carlos

Senior Software Engineer with extensive experience designing and delivering solutions ranging from corporate websites and customer-facing platforms to complex enterprise applications and cloud-native distributed systems. I specialize in scalable architectures, APIs, microservices, system integrations, and high-availability cloud environments, with a strong focus on performance, security, maintainability, and business alignment.

I have worked across the full software development lifecycle, from requirements analysis and architecture design to deployment, optimization, and modernization initiatives. My expertise includes full-stack development, backend services, cloud architecture, DevOps, CI/CD, and infrastructure automation.

A key area of my work is AI-powered automation. I help organizations integrate generative AI and intelligent workflows to automate business processes, improve productivity, and reduce operational effort. This includes LLM integrations, conversational assistants, document processing, semantic search, and AI-driven workflow orchestration.

I also apply an AI-First SDLC approach, leveraging AI throughout the development lifecycle for requirements analysis, architecture support, code generation, refactoring, test automation, documentation, code reviews, and deployment optimization.

My goal is to combine strong software engineering practices with modern AI capabilities to deliver reliable, scalable, and future-ready digital solutions that create measurable business value.
  • Spanish

    Native or bilingual

  • English

    Fluent

  • French

    Basic

Remote only
Primarily works remotely

Experience

  • Carrefour
    Senior Backend Engineer — Platform
    E-COMMERCE
    October 2025 - April 2026 (6 months)
    Madrid, Spain
    Core backend contributor on a global retail platform running on GCP, building the services that underpin millions of daily transactions.
    → Designed and implemented high-throughput REST microservices in Node.js/TypeScript deployed on GCP Cloud Run; defined API contracts and versioning strategies adopted across all platform teams.
    → Built real-time inventory event pipelines using GCP Pub/Sub and Cloud Functions; reduced inventory sync latency from minutes to under 5 seconds.
    → Implemented backend AI integrations (GCP AI Platform + Python) for supply chain anomaly detection; shipped from prototype to production in 6 weeks.
    → Applied FinOps backend optimisations — query caching with Redis, connection pooling, and autoscaling policies — cuting GCP costs by 20%.
    IT Architecture Google cloud Java Spring Boot GO Android
  • Nextlane (formerly Imaweb)
    Senior Backend Engineer — Platform Core
    AUTOMOBILE
    March 2022 - October 2025 (3 years and 7 months)
    Madrid, Spain
    Deep backend specialist responsible for the most complex and performance sensitive parts of a multi-tenant automotive SaaS platform.
    → Diagnosed and resolved critical production issues: race conditions in distributed transactions, N+1 query explosions, connection pool exhaustion under peak load — each traced to root cause at the architecture level.
    → Refactored core service boundaries to eliminate tight coupling; implemented event-driven communication between services, improving resilience and reducing cascading failure incidents by 35%.
    → Introduced structured observability (distributed tracing, structured logging, SLO-based alerting) across backend services using OpenTelemetry.
    PHP Node.js React.js React Native PostgreSQL
  • Freelance — Startups &SME Consulting
    Senior Full-Stack Engineer (Backend Focused)
    January 2007 - Today (19 years and 7 months)
    Primary backend engineer for multiple concurrent projects — sole owner of server-side architecture, data modelling, API design, and cloud infra.
    → Multi-tenant SaaS backends: Designed and coded data isolation strategies, subscription billing integrations, and role-based access control systems from scratch in Symfony and Node.js working on Cloud infrastructure.
    → Third-party API orchestration: Built robust integration layers for payment gateways, SMS/email providers, and ERP systems with retry logic, circuit breakers, and idempotency guarantees.
    → Database design: Modelled complex relational schemas (MySQL/PostgreSQL) and document stores (MongoDB); implemented migration strategies for live systems without downtime.
    MySQL Redis AWS MongoDB Symfony

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Education

  • Data Science &AI with
    Platzi
    2023
    Data Science &AI with
  • Technical Engineering in Computer Science
    Universidad Carlos III
    2008
    Technical Engineering in

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