Atomic ObjectDoug Shipp5 min readintermediate
What a Write-Only Architecture Bought Our Health App
Summary
A health‑assessment app was built as a write‑only pipeline: it encrypts survey answers, writes them to a staging collection that the vendor can read, then hands them off to the EHR via cloud functions. This eliminates PHI exposure for the developer team but adds operational friction—debugging requires only IDs and ciphertext, resuming surveys can’t be done server‑side, and failures in the handoff…
- Write‑only architecture can enforce a strict data‑ownership boundary, making compliance arguments clearer for security audits.
- Debugging without PHI requires indirect methods (IDs, timestamps) and can slow incident resolution.
- Server‑side resume functionality is impossible without read access; client‑side storage is a workaround but loses durability across device changes.
- Separating data handling from the front‑end allows swapping UI frameworks (e.g., React Native to web) without touching encryption or integration code.
In regulated domains like healthcare, minimizing PHI exposure reduces compliance risk and simplifies security reviews, but it also shifts the burden of observability and resilience to the downstream services. Teams must weigh the security benefits against the operational costs of debugging and feat…
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