Build a SMART on FHIR App in 30 Minutes

SMART on FHIR is how apps talk to electronic health records. It's OAuth 2.0 with a few healthcare-specific conventions: a discovery document that tells your app where to authenticate, scopes that map to FHIR resource types, and a launch context that tells you which patient you're looking at. This tutorial follows SMART App Launch STU2.1 — the current published standard. If you've built an OAuth login flow before, you already understand 80% of it. The other 20% is what this covers. We're going to build a standalone SMART app that authenticates against a FHIR server, fetches a patient's vital signs, and renders interactive charts — heart rate, blood pressure, SpO2, temperature, weight, and BMI. The whole thing fits in a single index.html file. No React, no bundler, no npm install. Just a text editor and a browser. By the end you'll have a working app and a mental model for how every SMART on FHIR app works under the hood — whether it's a one-page demo or a production clinical decision su