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DOUGLAS ROJAS.

About

Engineer first, stack second.

Software engineer in Bolivia working on healthcare interoperability, industrial edge platforms, and performance. Here is how I got here and how I work.

Douglas Rojas Vargas

Douglas Rojas Vargas

Software Engineer — healthcare interoperability, industrial edge, performance

Bolivia · EN / ES · UTC−4

Bio

I build software for domains where being wrong is expensive: healthcare data interoperability, claims processing, and industrial edge systems. Today I work full time on the Helios FHIR Server at Helios Software, a SQL-on-FHIR engine with a Rust core and Python interface, and I co-founded Hellium Works. Before that: X12/EDI claims validation for Labcorp, OPC UA connectivity for industrial HVAC platforms with Fireball Industries, and three years of fullstack work at AssureSoft.

The details live in the case studies — browse the work

Operating principles

  • Start from the problem. The stack is a consequence, not an identity.

  • Measure before and after. An optimization without numbers is an anecdote.

  • Prefer boring, inspectable systems. Clinical and industrial data leaves no room for clever surprises.

  • Write it down. Architecture, decisions, and tradeoffs belong in documents, not in heads.

Career context

I started in mechatronics engineering and moved into software through industrial automation and applied machine learning. The through-line since has been systems that sit close to the physical world or to regulated data: magnetic-field modeling for civil aviation, sign-language recognition research, industrial edge platforms, and healthcare data infrastructure. I work from Bolivia, in English and Spanish.

Experience

2021 — Present

  1. Jun 2025 — Present

  2. Aug 2025 — Present

    • Added MongoDB backend support to the Helios FHIR Server and improved its HL7 FHIRPath validation engine.
    • Built pysof, the Python bindings for the Rust SQL-on-FHIR query engine, so Python applications can query FHIR resources directly.
    • Labcorp: developed a full-stack claims evaluation platform processing X12 EDI 837 and 381 transactions across 30+ states.
    • Labcorp: improved batch validation pipelines and reporting, and delivered the Optum Validation API integration for automated claim verification.
    HL7 FHIRRustPythonX12/EDI

  3. Jan 2021 — Present

    • Fireball Industries: Ignition Edge gateways, OPC UA connectivity, CODESYS controllers and React connectivity apps for Trane.
    • Jaraneo: backend workflow and build-time improvements, CI/CD on GCP with a 70% coverage gate, onboarding and mentoring.
    • Quantum Serve: migrated the frontend from Create React App to Vite, introduced Redux Toolkit, and refactored the UI toward a frontend-friendly architecture.
    OPC UANode.jsReactCI/CD

  4. Jan 2022 — Aug 2025

    • SOLO: cut PDF report generation from 8 minutes to 4 with Puppeteer on GCP.
    • SOLO: cut shade-analysis computation from 10 minutes to 10 milliseconds with Python and NumPy on Google Kubernetes Engine, and improved projection algorithms with linear algebra.
    • LigaX: co-led a small team to an MVP of a sports social network in three months; Solidity contracts on Ethereum, React with Redux Toolkit, AWS S3 and Lambda video watermarking with ffmpeg.
    • Fostered clean coding and TDD through code reviews and mentoring; supervised three developers.
    PythonGCPReactPerformance