> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kvant.sbs/jeston/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

# Authentication

***

## Platform · Authentication

> **Platform concern** — Separate proving who someone is from deciding what that person may do.

Signed sessions, secure cookies, authorization checks, rotation, and revocation behavior.

### Key concepts

<Columns cols={3}>
  <Card title="Authentication" icon="sparkles">
    401
  </Card>

  <Card title="Authorization" icon="shield-check">
    403
  </Card>

  <Card title="Revocation" icon="gauge-high">
    Immediate or bounded
  </Card>
</Columns>

### Operating model

```mermaid placement="top-right" theme={null}
flowchart LR
    credentials[Credentials] --> identity[Identity provider]
    identity --> session[Signed session]
    session --> request[Request context]
    request --> policy[Authorization policy]
    policy --> resource[Protected resource]
```

### Decisions to make before production

| Decision       | Recommended posture  | Failure it prevents                 |
| -------------- | -------------------- | ----------------------------------- |
| Authentication | 401                  | Identity absent or invalid.         |
| Authorization  | 403                  | Identity present but policy denies. |
| Revocation     | Immediate or bounded | Document the security tradeoff.     |

### Boundary and failure behavior

Authentication bugs become data-boundary bugs when identity and tenant scope are implicit.

### Questions for review

| Question                        | Answer to document                                                                            |
| ------------------------------- | --------------------------------------------------------------------------------------------- |
| Where should authorization run? | Near the resource access, not only in the route or UI.                                        |
| When rotate keys?               | Before expiry or compromise forces an emergency change; support overlap where necessary.      |
| What is logout?                 | A client action plus server-side invalidation strategy when immediate revocation is required. |

### Implementation notes

| Engineering move               | Guidance                                                         |
| ------------------------------ | ---------------------------------------------------------------- |
| **Choose the identity source** | Define credentials, external provider, or service identity.      |
| **Issue a bounded session**    | Set expiry, cookie flags, rotation, and revocation expectations. |
| **Authorize every resource**   | Check ownership or capability at the domain boundary.            |
| **Exercise recovery**          | Test expiry, logout, key rotation, replay, and missing identity. |

### Decision lens

| Mode             | Practical emphasis                                                         |
| ---------------- | -------------------------------------------------------------------------- |
| **Browser**      | HttpOnly, Secure, SameSite, and CSRF posture.                              |
| **API**          | Bearer or service credentials with explicit scopes.                        |
| **Internal job** | Carry actor and tenant context without pretending it is a browser session. |

## Related topics

<Columns cols={3}>
  * [shield-halved · **Harden identity**](/jeston/jeston/platform/security) — Read the focused guide for this boundary.
  * [building · **Apply tenancy**](/jeston/jeston/start/saas-starter) — Read the focused guide for this boundary.
  * [globe · **Return auth errors**](/jeston/jeston/reference/http-contracts) — Read the focused guide for this boundary.
</Columns>

## References

[1]: https://github.com/jeffersoncampos12p-dev/jeston "Jeston source repository"

[2]: https://www.npmjs.com/package/@kvantjs/jeston "Jeston package on npm"

[3]: https://nodejs.org/api/http.html "Node.js HTTP API"

[4]: https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal "AbortSignal Web API"

[5]: https://react.dev/reference/react-dom/server "React server rendering APIs"

[6]: https://www.typescriptlang.org/docs/handbook/intro.html "TypeScript handbook"