Application Engineering

Choose architecture from product contracts, data ownership, and operational constraints. Framework idioms refine the design; they do not replace it.

Establish the system contract

Identify users, critical journeys, trust boundaries, data lifecycle, availability and latency expectations, deployment environment, and compatibility commitments. Inspect the existing architecture and authoritative documentation before proposing version-sensitive APIs.

Route to the relevant reference:

• system shape, module ownership, and frontend composition: architecture.md;
• HTTP/API contracts and integrations: api-and-contracts.md;
• schemas, queries, transactions, migrations, and hosted Postgres: data-and-persistence.md;
• Python, Node, FastAPI, Django, React, Next.js, or React Native details: runtime-and-frameworks.md.

Design boundaries first