> For the complete documentation index, see [llms.txt](https://ocx.gitbook.io/ocx-doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ocx.gitbook.io/ocx-doc/auth.md).

# auth

Endpoints for Sign-In With Ethereum (SIWE) and session management. For the full background on the flow, see [Authentication → SIWE](file:///7302513/authentication/siwe.md).

## POST /auth/nonce

Request a nonce for the user to sign.

**Auth**: none.

**Request**

```json
{ "walletAddress": "0xYourAddress" }
```

**Response**

```json
{ "nonce": "a1b2c3d4..." }
```

**Errors**

| Status | When                                 |
| ------ | ------------------------------------ |
| 400    | `walletAddress` missing or malformed |

## POST /auth/siwe

Verify a signed SIWE message and establish a session.

**Auth**: none.

**Request**

```json
{
  "message": "api.ocx.global wants you to sign in with your Ethereum account...",
  "signature": "0x..."
}
```

**Response** — sets `Set-Cookie: astra_session=<jwt>; HttpOnly; Secure; SameSite=None; Path=/; Max-Age=604800`.

```json
{
  "userId": "01HW...",
  "walletAddress": "0xYourAddress"
}
```

**Errors**

| Status | `code`                 | When                                    |
| ------ | ---------------------- | --------------------------------------- |
| 400    | `INVALID_SIWE_MESSAGE` | Message is malformed                    |
| 400    | `NONCE_MISMATCH`       | Nonce doesn't match one we issued       |
| 401    | `INVALID_SIGNATURE`    | Signature doesn't match claimed address |

## GET /auth/me

Returns the currently authenticated user, or `null` if not signed in.

**Auth**: optional (this endpoint intentionally returns `null` rather than 401 for unauthenticated callers).

**Response (signed in)**

```json
{
  "userId": "01HW...",
  "walletAddress": "0xYourAddress"
}
```

**Response (not signed in)**

```json
null
```

## POST /auth/logout

Revokes the session and clears the cookie.

**Auth**: required.

**Response**

```json
{ "message": "Logged out" }
```


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