# GET /api/merchants/registers/by-legacy-number/{legacyNumber}

Register: resolves a register by its legacy numeric key within the caller's own merchant.

Example: `GET /api/merchants/registers/by-legacy-number/41`.


This action throws where the interface returns null: over HTTP a null would be a 204 with an
empty body, which reads as success. 404 is the published contract for the route.



The merchant is deliberately not on this path, since the key resolves against the caller's
own merchant. The `by-legacy-number` literal keeps a bare `registers/{legacyNumber}`
from sitting beside `merchants/{id}` as a sibling-parameter disagreement, which aborts
SDK generation; it is safe in the other direction because such a literal collides only with a
sibling parameter of the same name.

**Operation ID:** `registersFindRegisterByLegacyNumber`

## Authorization

Requires: Merchants.SelfServiceSettings, merchant scope.

Required permissions:
- `Merchants.SelfServiceSettings`

## Parameters

| Name | In | Required | Type | Description |
| --- | --- | --- | --- | --- |
| legacyNumber | path | yes | integer(int64) | The legacy numeric register key. |
| suppressNulls | query | no | boolean | If true, omit properties with null values. |

## Responses

### 200

OK

**Content type:** `application/json`

Schema: `MerchantRegisterLegacyMatchDto`

Properties:
- `merchantId` (string(uuid)): The merchant that owns the register.
- `register` (object): The resolved register, including its `legacyNumber`.

### 403

Forbidden

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 401

Unauthorized

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 400

Bad Request

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 404

Not Found

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 501

Not Implemented

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 500

Internal Server Error

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### default

The request failed. The body carries the standard error envelope: a machine-readable `error.code`, a human-readable `error.message`, and `error.validationErrors` when the failure was a validation rejection. See the error-code reference in this document's description for the values `error.code` can take.

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 429

The request was refused because a rate limit was exceeded, or because something a later retry can clear stopped it. A rate limit refusal carries an `application/problem+json` body: wait at least the interval `Retry-After` names before retrying, then back off. Limits are tuned per deployment, so read the allowance from the response headers rather than assuming a fixed ceiling. Any other refusal carries the standard error envelope as `application/json`, and its `error.code` names the cause.

**Content type:** `application/problem+json`

Schema: `RateLimitProblemDetails`

Properties:
- `type` (string) required: The problem type identifier. Always the same value: the failure is the status code itself,  so there is no sub-type for a caller to branch on.
- `title` (string) required: A short, human-readable summary of the problem type.
- `status` (integer(int32)) required: The HTTP status code, repeated in the body as the problem-details format defines.
- `detail` (string) required: A human-readable explanation of this occurrence of the problem.
- `retryAfterSeconds` (integer(int32)) required: How long to wait before retrying, in whole seconds, carrying the same figure as the  `Retry-After` header. Always at least one: a value of zero would invite an immediate  retry that is certain to be rejected again.

**Content type:** `application/json`

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

## Example request

Every block below sends the same request. Replace {{BASE_URL}} with the address of the API you are calling and {{API_KEY}} with your own key.

### cURL

```bash
curl -X GET "{{BASE_URL}}/api/merchants/registers/by-legacy-number/{legacyNumber}" \
  -H "api-key: {{API_KEY}}"
```

### PowerShell

```powershell
$headers = @{
    'api-key' = '{{API_KEY}}'
}

$response = Invoke-RestMethod -Method GET -Uri '{{BASE_URL}}/api/merchants/registers/by-legacy-number/{legacyNumber}' `
    -Headers $headers
```

### TypeScript (SDK)

```bash
npm install @winkpg/winkpg-api
```

```typescript
import { Configuration, MerchantsApi } from '@winkpg/winkpg-api';

const api = new MerchantsApi(new Configuration({
  basePath: '{{BASE_URL}}',
  apiKey: '{{API_KEY}}',
}));

const { data } = await api.registersFindRegisterByLegacyNumber(1);
```

### TypeScript (raw HTTP)

```typescript
const response = await fetch('{{BASE_URL}}/api/merchants/registers/by-legacy-number/{legacyNumber}', {
  method: 'GET',
  headers: {
    "api-key": "{{API_KEY}}",
  },
});

const data = await response.json();
```

### C# (SDK)

```bash
dotnet add package WinkPg.Api.Client
```

```csharp
using WinkPg.Api.Client.Api;
using WinkPg.Api.Client.Client;

var config = new Configuration { BasePath = "{{BASE_URL}}" };
config.AddApiKey("api-key", "{{API_KEY}}");

var api = new MerchantsApi(config);
var result = await api.RegistersFindRegisterByLegacyNumberAsync(1);
```

### C# (raw HTTP)

```csharp
using var http = new HttpClient { BaseAddress = new Uri("{{BASE_URL}}") };

var request = new HttpRequestMessage(new HttpMethod("GET"), "/api/merchants/registers/by-legacy-number/{legacyNumber}");
request.Headers.Add("api-key", "{{API_KEY}}");

var response = await http.SendAsync(request);
response.EnsureSuccessStatusCode();
var json = await response.Content.ReadAsStringAsync();
```

### Python (SDK)

```bash
pip install winkpg-api
```

```python
import winkpg_api

configuration = winkpg_api.Configuration(host="{{BASE_URL}}")
configuration.api_key["ApiKey"] = "{{API_KEY}}"

with winkpg_api.ApiClient(configuration) as client:
    api = winkpg_api.MerchantsApi(client)
    result = api.registers_find_register_by_legacy_number(1)
```

### Python (raw HTTP)

```bash
pip install requests
```

```python
import requests

headers = {
    "api-key": "{{API_KEY}}",
}

response = requests.request(
    "GET",
    "{{BASE_URL}}/api/merchants/registers/by-legacy-number/{legacyNumber}",
    headers=headers,
)
response.raise_for_status()
data = response.json()
```

## See also

- [All documentation](https://devportal-simpay-sbx.winkpg.io/llms.txt): the machine-readable index of every public page on this site.