> ## Documentation Index
> Fetch the complete documentation index at: https://docs.0xarchive.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Get SIWE challenge message JSON Schema

> Get SIWE challenge message JSON Schema contract. Includes route metadata, request parameters, response statuses, examples, and JSON fields for implementation.

Source OpenAPI: 0xArchive API 1.8.0; 227 paths; 217 component schemas.

Get a single-use SIWE (Sign-In with Ethereum) challenge message for existing-wallet sign-in, wallet key management, or paid x402 access. The nonce expires after 10 minutes. A challenge does not create a Free account.

## Route Metadata

| Field | Value |
| - | - |
| Method | `POST` |
| Path | `/v1/auth/web3/challenge` |
| operationId | `web3Challenge` |
| Tag | Web3 Authentication |
| Family | Web3 Auth |
| Deprecated or legacy | no |

## Human endpoint reference

Open [`POST /v1/auth/web3/challenge`](/api-reference/web3-authentication/get-siwe-challenge-message) for authentication, parameters, responses, and examples.

## Request Body

### application/json

```json theme={"theme":"github-dark"}
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "web3Challenge request body",
  "type": "object",
  "required": [
    "address"
  ],
  "properties": {
    "address": {
      "description": "Ethereum wallet address",
      "type": "string",
      "example": "0x742d35Cc6634C0532925a3b844Bc9e7595f2bD18"
    }
  }
}
```

## Response Contracts

### Status 200

SIWE challenge message

#### application/json

```json theme={"theme":"github-dark"}
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "web3Challenge response 200",
  "type": "object",
  "properties": {
    "message": {
      "description": "SIWE message to sign with personal_sign (EIP-191)",
      "type": "string"
    },
    "nonce": {
      "description": "Single-use nonce (expires after 10 minutes)",
      "type": "string"
    }
  }
}
```

### Status 400

Invalid request

#### application/json

```json theme={"theme":"github-dark"}
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "web3Challenge response 400",
  "description": "Error response",
  "type": "object",
  "properties": {
    "code": {
      "description": "HTTP status code",
      "type": "integer"
    },
    "error": {
      "description": "Error message",
      "type": "string"
    },
    "error_code": {
      "description": "Machine-readable error code. Common values: `invalid_query_params` (a query parameter failed to parse or validate) and `invalid_path_params` (a path parameter failed to parse). Other endpoint-specific codes exist; treat unknown codes as generic errors of the given HTTP status.",
      "type": "string"
    },
    "param": {
      "description": "The parameter at fault, when the error is about one parameter.",
      "type": "string"
    },
    "request_id": {
      "description": "Unique request ID for support",
      "type": "string",
      "format": "uuid"
    },
    "success": {
      "description": "Always false on an error.",
      "type": "boolean",
      "example": false
    }
  }
}
```

##### OpenAPI example

```json theme={"theme":"github-dark"}
{
  "code": 400,
  "error": "Failed to deserialize query string: limit: invalid digit found in string",
  "error_code": "invalid_query_params",
  "param": "limit",
  "request_id": "3f2a9c71-5b0e-4d68-9a4c-7e1d2b6f8a05",
  "success": false
}
```

### Status 429

Rate limit exceeded

#### application/json

```json theme={"theme":"github-dark"}
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "web3Challenge response 429",
  "description": "Error response",
  "type": "object",
  "properties": {
    "code": {
      "description": "HTTP status code",
      "type": "integer"
    },
    "error": {
      "description": "Error message",
      "type": "string"
    },
    "error_code": {
      "description": "Machine-readable error code. Common values: `invalid_query_params` (a query parameter failed to parse or validate) and `invalid_path_params` (a path parameter failed to parse). Other endpoint-specific codes exist; treat unknown codes as generic errors of the given HTTP status.",
      "type": "string"
    },
    "param": {
      "description": "The parameter at fault, when the error is about one parameter.",
      "type": "string"
    },
    "request_id": {
      "description": "Unique request ID for support",
      "type": "string",
      "format": "uuid"
    },
    "success": {
      "description": "Always false on an error.",
      "type": "boolean",
      "example": false
    }
  }
}
```

##### OpenAPI example

```json theme={"theme":"github-dark"}
{
  "code": 429,
  "error": "Rate limit exceeded"
}
```


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