# State 005 Fidelity Profile

> For the complete documentation index, see [llms.txt](https://deploy-preview-472--lucky-concha-f3599f.netlify.app/llms.txt).

This profile captures the required technical shape for state `005-postgres-database-replacement`.

## Runtime Stack Deltas From State 004

| Concern | State 004 | State 005 |
| --- | --- | --- |
| Database runtime | H2 service process + H2 web console | PostgreSQL container (`postgres:16-alpine`) |
| DB access protocol | H2 TCP / PG emulation | Native PostgreSQL (5432) |
| DB init path | H2 RunScript | PostgreSQL init SQL via `/docker-entrypoint-initdb.d` |
| Ingress model | NGINX | NGINX (unchanged) |
| Runtime model | Docker Compose | Docker Compose (unchanged) |

## PostgreSQL Baseline Constraints

*   PostgreSQL image remains lightweight and local-friendly.
*   State uses deterministic schema and seed data from a committed init script.
*   Account sequence semantics remain compatible (`accounts_seq`).
*   DB-dependent service startup is gated on PostgreSQL readiness.

## Closeness Policy

State `005` is architecture-close to `004` with one intentional replacement axis: database runtime engine.

Changes expected:

*   replacement of H2 runtime with PostgreSQL container,
*   datasource and driver updates in DB-dependent services,
*   no intentional REST/event contract drift.