Juan Pablo Castro

Castro Solutions

Freelance Software Engineer & AI Product Engineer

Spain in remote

• • Building digital products for clients and developing my own AI-enabled products, combining full-stack delivery, architecture and technical leadership.
• • Shipped two products of my own: ChacharApp (local AI dictation for macOS, Whisper on the Apple Neural Engine) and Salturno (shift-rota calendar for iOS).
• • Client delivery from problem definition to production: product discovery, full-stack TypeScript, AWS infrastructure and the operational work that keeps it running.
• • AI engineering on both sides of the work: evals, guardrails and deterministic fallbacks in the products; spec-driven workflows and agentic harness design in the process.

TypeScript NestJS Next.js AWS Terraform PostgreSQL Swift · SwiftUI Claude Code

Capgemini

Tech Lead & Software Architect

Valencia, Spain (Remote)

• • Led the architecture and hands-on delivery of Fast Checkout, a product connecting e-commerce, shipping and payment flows for PostNL's Digital Lab.
• • Translated ambiguous business and product requirements into system boundaries, technical flows and production-ready capabilities.
• • Coordinated product, frontend, backend, plugin and platform stakeholders across multiple integrations, engaging directly with client decision-makers.
• • Designed cloud-native TypeScript services and infrastructure on AWS: Terraform IaC, Azure DevOps CI/CD, autoscaling and queue-based workflows with end-to-end traceability.
• • Led a team of 5 — mentoring, roadmap, prioritisation and quality gates — balancing delivery speed, security, maintainability and integration complexity. Hosted architecture talks in Capgemini's Architects department.

Terraform (AWS) Azure DevOps Docker NestJS Prisma ORM Next.js React Angular

Tecon (Ekiba)

Full-Stack Developer

Parque Industrial del Elche, Alicante, Spain

• • Full-stack design and development from scratch of GICA, the wildfire response management system for GEACAM (regional government of Castilla-La Mancha).
• • Built the back-office to manage extinction units, shift changes and approvals, and to generate the daily reports (worked hours, mileage, overtime) feeding payroll and operations.
• • Led requirements gathering and system design directly with the client.

Angular 2+ NestJS Express Node GitLab PLESK Bash Linux

Cognizant

Programmer Analyst / Software Developer

Parque Tecnológico de Boecillo, Valladolid, Spain

• • Functional analysis and development of web applications with a strong client focus.
• • Used modern DevOps practices with continuous integration, following the Scrum framework.

Angular 2+ TypeScript RxJS HTML5 SCSS Jasmine Spring (Java) Git Bitbucket JIRA

Cognizant

Junior Full-Stack Developer

Parque Tecnológico de Boecillo, Valladolid, Spain

• • Development and maintenance of web components (logic and styling) used across projects.
• • Unit testing with Karma and Jasmine.
• • Development of Python microservices with scikit-learn to make predictions.
• • Kanban methodology.

Angular 2+ JavaScript RxJS HTML5 SCSS Karma-Jasmine Spring (Java) Git Bitbucket JIRA

Salamanca, Spain

• • Study and integration of agile frameworks with the CMMI (Capability Maturity Model Integration) quality standard.
• • Development of internal web applications for Google Assistant using DialogFlow (NLP) through JavaScript.
• • Publication of articles on the ViewNEXT / USAL blog.
• • Collaboration in introductory workshops on agile frameworks.

Angular 2+ JavaScript RxJS HTML5 SCSS Karma-Jasmine Spring (Java) Git Bitbucket JIRA