---
title: Articles · Dimitrios Rarras
description: >-
  Technical deep-dives by Dimitrios Rarras on headless commerce with Medusa.js, FHIR-compliant healthcare software, and
  embedded MCP servers in TypeScript.
lang: en
source: https://jimrarras.com/en/articles/
fetched: '2026-08-24T14:13:23.884Z'
---

Technical deep-dives by Dimitrios Rarras on headless commerce with Medusa.js, FHIR-compliant healthcare software, and embedded MCP servers in TypeScript.

- [![](https://jimrarras.com/images/projects/migraine-tracker/hero.webp)](https://jimrarras.com/en/fhir-mobile-health-react-native-observation/)
  
  Healthcare
  
  ### [Real FHIR 4.0.1 in a Mobile Health App: Beyond the Marketing Claim](https://jimrarras.com/en/fhir-mobile-health-react-native-observation/)
  
  Most mobile health apps claim FHIR compatibility and ship ad-hoc JSON dressed up to look like FHIR. Real FHIR 4.0.1 means a neurologist can import your export straight into their EHR. Here's how to model a migraine episode as an Observation resource with SNOMED CT + HL7 terminology, what verification actually looks like, and the React Native + Expo decisions that hold the rest of the stack together.
  
  9 min read
  
- [![](https://jimrarras.com/images/projects/rorsa-tools/hero.webp)](https://jimrarras.com/en/embedded-mcp-servers-production-typescript/)
  
  AI
  
  ### [Embedded MCP Servers in Production: AI Agents Inside Your TypeScript Backend](https://jimrarras.com/en/embedded-mcp-servers-production-typescript/)
  
  The Model Context Protocol (MCP) is usually shown as a standalone server, but the real production unlock is embedding an MCP server inside your existing TypeScript backend so Claude agents make direct tool calls against your data without an intermediate REST hop. Two real-world MCP shipments, the @modelcontextprotocol/sdk decisions, and when to embed vs externalise.
  
  7 min read
  
- [![](https://jimrarras.com/images/projects/heartbeat-pharmacy/hero.webp)](https://jimrarras.com/en/headless-commerce-medusa-vs-shopify-plus/)
  
  E-commerce
  
  ### [Headless Commerce with Medusa.js: Why Heartbeat Pharmacy Didn't Go With Shopify Plus](https://jimrarras.com/en/headless-commerce-medusa-vs-shopify-plus/)
  
  Shopify Plus charges a percentage of every transaction and locks the data layer behind a tenant boundary you don't control. Medusa.js doesn't, and it's one of the few headless commerce platforms that fits Greek bank integrations, marketplace feeds, and real B2B workflows without a paid app marketplace.
  
  8 min read