Backend services with Java/Spring Boot, REST APIs, PostgreSQL, authentication, and CI/CD
Curriculum vitae
Alejandro Saez Castells — Senior Backend & Smart Contract Engineer CV
Experience across production backend services, smart contracts, Web3 integrations, full-stack delivery, and industrial automation.
Current technical focus
Backend systems, smart contracts, and operational workflows.
Smart contracts with Solidity/EVM, Foundry, access control, state machines, and tokenized workflows
Web3 integrations involving wallets, contract interactions, APIs, and user-facing flows
Real-world workflow systems involving roles, permissions, deadlines, KPIs, and auditability
Experience
Engineering background at a glance.
2023 - Present
A3M Global Monitoring
Java Backend / Blockchain Developer
- Developed scalable backend services with Java and Spring Boot, delivering secure REST APIs.
- Implemented authentication and access-control patterns using Keycloak and documented APIs with OpenAPI/Swagger.
- Built internal backend functionality including a translation API with provider integrations, caching, PostgreSQL statistics, and CI/CD workflows.
Recent project
AtlasOra
Full-Stack Developer
- Contributed to a live vacation-rental marketplace focused on trusted listings, user verification, search experience, and guest/host interactions.
- Implemented and improved KYC/user verification flows, marketplace search behavior, and Web2/Web3 integration points.
2022 - 2024
Defdone
Full-Stack & Web3 Developer
- Built full-stack applications with React, Node.js, and TypeScript.
- Implemented Web3 integrations, wallet flows, contract interactions, API layers, and Casper ecosystem tooling including Fondant.
2014 - 2023
Industrial automation: Ford, Gestamp, SEAT and others
Automation Engineer
- Programmed and commissioned automated production systems across Europe under tight uptime and safety constraints.
- Applied process modeling and root-cause analysis, transferable to designing robust on-chain and backend workflows.
Selected evidence