Open to opportunities

Daniel Castro

@danielcastro3

Message

I build reliable backend systems for high-volume, compliance-critical data platforms.

Germany

Message

What I'm looking for

I'm looking to apply my production reliability, system design, and security discipline to backend systems for regulated financial products.

At Redborder, I maintained and debugged distributed backend services processing real-time network data from 10,000+ critical healthcare devices. I resolved Kafka and Logstash pipeline failures, production memory issues, recurring service crashes, and PostgreSQL-backed API reliability problems in a regulated environment.

I also built LoginValidator, a Go and Redis-based real-time authentication anomaly detection service with Prometheus and Grafana observability. Through freelance cybersecurity consulting, I’ve assessed data-handling practices and implemented hardened configurations to reduce client exposure.

Experience

Work history, roles, and key accomplishments

Cyber Security Consultant

Freelance

Nov 2025 - May 2026 (6 months)

Assessed a small client's data-handling and security practices, then implemented hardened configurations and practical guidance to reduce exposure.

Security Hardening

Backend Developer

Redborder

Mar 2024 - Nov 2025 (1 year 8 months)

Maintained and debugged backend services in a distributed, multi-service platform processing high-volume network data from 10,000+ critical healthcare devices in a regulated, compliance-critical production environment. Built and maintained REST APIs backed by PostgreSQL, and used Druid queries to support data-processing workflows, operations, and production troubleshooting.