# Session Module Overview

The Session module supplies opinionated helpers for signing, storing, and validating user sessions.
It focuses on stateless HMAC cookies by default but exposes hooks so teams can plug in Redis or
other backends when they need centralised storage.

## Key Capabilities

- **Session token helpers** – Deterministic signing and verification using HMAC (HS256) with rolling
  expiration support.
- **Cookie utilities** – Functions for issuing HTTP-only cookies with secure defaults for FastAPI
  projects.
- **NestJS support** – A TypeScript service mirrors the Python runtime so client and server stacks
  share the same semantics.
- **Integration tests** – Repository smoke tests ensure signing keys are respected and refresh logic
  behaves predictably.

## Security considerations

This module may touch sensitive data or privileged actions depending on how it is configured.

- Security: document configuration boundaries and expected trust assumptions.
- Threat model: consider abuse cases (rate limiting, replay, injection) relevant to your
  environment.

If you operate in a regulated environment, include a brief audit trail strategy (what you log,
retention, who can access).
