# POST /api/invoicing/invoices/tax-rate-lookup

Invoices: Looks up a line's sales-tax rate from the merchant biller's tax provider.

Resolves the origin from the merchant's default shipping origin (falling back to
`billerSnapshot`) and the destination from `recipientSnapshot` (falling back to a
customer recipient's address on file), then asks the merchant's bound provider for the
combined rate. The answer is in percent units (a provider rate of 0.0975 is returned as 9.75),
ready to store as the line's `taxRatePercent` alongside `taxRateSource` = Provider
and the returned `providerName`. The line's `taxCode` is never sent to the provider.

**Operation ID:** `invoiceTaxRateLookupLookup`

## Authorization

Requires: Invoicing.Invoices, merchant scope.

Required permissions:
- `Invoicing.Invoices`

## Parameters

| Name | In | Required | Type | Description |
| --- | --- | --- | --- | --- |
| suppressNulls | query | no | boolean | If true, omit properties with null values. |

## Request Body

The biller, the recipient, and the optional address overrides.

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

Schema: `InvoiceTaxRateLookupInput`

Properties:
- `billerId` (string(uuid)) required: The biller whose tax provider binding performs the lookup. Must be a merchant.
- `billerType` (object): The biller's party type. Anything other than `Merchant` is refused.
- `recipientType` (object): The recipient's party type. Only a `Customer` recipient has an address on file to fall back to.
- `recipientId` (string(uuid)): The recipient, when one has been chosen. Optional: a supplied `recipientSnapshot` stands in for it.
- `recipientSnapshot` (object): Optional destination address. When supplied with a street and a state it is used as the  destination instead of the recipient's address on file. Conditional: When RecipientSnapshot is not null.
- `billerSnapshot` (object): Optional origin address. Used only when the merchant has no default shipping origin. Conditional: When BillerSnapshot is not null.

**Content type:** `text/json`

Schema: `InvoiceTaxRateLookupInput`

Properties:
- `billerId` (string(uuid)) required: The biller whose tax provider binding performs the lookup. Must be a merchant.
- `billerType` (object): The biller's party type. Anything other than `Merchant` is refused.
- `recipientType` (object): The recipient's party type. Only a `Customer` recipient has an address on file to fall back to.
- `recipientId` (string(uuid)): The recipient, when one has been chosen. Optional: a supplied `recipientSnapshot` stands in for it.
- `recipientSnapshot` (object): Optional destination address. When supplied with a street and a state it is used as the  destination instead of the recipient's address on file. Conditional: When RecipientSnapshot is not null.
- `billerSnapshot` (object): Optional origin address. Used only when the merchant has no default shipping origin. Conditional: When BillerSnapshot is not null.

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

Schema: `InvoiceTaxRateLookupInput`

Properties:
- `billerId` (string(uuid)) required: The biller whose tax provider binding performs the lookup. Must be a merchant.
- `billerType` (object): The biller's party type. Anything other than `Merchant` is refused.
- `recipientType` (object): The recipient's party type. Only a `Customer` recipient has an address on file to fall back to.
- `recipientId` (string(uuid)): The recipient, when one has been chosen. Optional: a supplied `recipientSnapshot` stands in for it.
- `recipientSnapshot` (object): Optional destination address. When supplied with a street and a state it is used as the  destination instead of the recipient's address on file. Conditional: When RecipientSnapshot is not null.
- `billerSnapshot` (object): Optional origin address. Used only when the merchant has no default shipping origin. Conditional: When BillerSnapshot is not null.

## Responses

### 200

The provider's rate in percent units.

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

Schema: `InvoiceTaxRateLookupResultDto`

Properties:
- `ratePercent` (number(double)): The combined sales-tax rate in percent units, rounded to four decimals.
- `jurisdiction` (string): One display string naming the jurisdictions the rate is built from, bounded to  `MaxTaxJurisdictionLength` so it fits the line's jurisdiction field.
- `providerName` (string): The provider that answered, as the line records it in `TaxRateProviderName`.
- `normalizedAddress` (string): The provider's normalised form of the address it rated, when it reported one.
- `isFreightTaxable` (boolean): Whether the provider reports shipping as taxable at the rated location.

### 400

The biller is not a merchant (`Invoicing:TaxRateLookup:BillerNotMerchant`). Only a
merchant holds a tax provider binding; a reseller or gateway-owner biller uses its own tax
rate catalog instead.

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

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 404

The caller's biller scope does not cover the requested biller
(`Invoicing:Biller:ForeignBillerNotAllowed`). Reported as not-found rather than
forbidden so the response cannot be used to probe which billers exist.

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

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 409

The lookup cannot run as things stand: the merchant has no enabled, deployed provider
(`Invoicing:TaxRateLookup:ProviderUnavailable`); no origin address could be resolved
(`Invoicing:TaxRateLookup:NoOriginAddress`); no destination address could be resolved
(`Invoicing:TaxRateLookup:NoDestinationAddress`); or the provider answered with a
failure (`Invoicing:TaxRateLookup:ProviderFailed`), whose normalised error codes travel
in the error's `data.errorCodes`.

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

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 403

Forbidden

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

Schema: `RemoteServiceErrorResponse`

Properties:
- `error` (RemoteServiceErrorInfo)

### 401

Unauthorized

**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.

The request body is a InvoiceTaxRateLookupInput. See the Request body section below for its fields.

### cURL

```bash
curl -X POST "{{BASE_URL}}/api/invoicing/invoices/tax-rate-lookup" \
  -H "api-key: {{API_KEY}}" \
  -H "Content-Type: application/json" \
  -d '{
  "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
}'
```

### PowerShell

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

$body = @'
{
  "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
}
'@

$response = Invoke-RestMethod -Method POST -Uri '{{BASE_URL}}/api/invoicing/invoices/tax-rate-lookup' `
    -Headers $headers -ContentType 'application/json' -Body $body
```

### TypeScript (SDK)

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

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

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

const { data } = await api.invoiceTaxRateLookupLookup({
  "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
});
```

### TypeScript (raw HTTP)

```typescript
const response = await fetch('{{BASE_URL}}/api/invoicing/invoices/tax-rate-lookup', {
  method: 'POST',
  headers: {
    "api-key": "{{API_KEY}}",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
  }),
});

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;
using System.Text.Json;

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

var api = new InvoicingApi(config);
var body = JsonSerializer.Deserialize<InvoiceTaxRateLookupInput>("""
    {
      "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
    }
    """);

var result = await api.InvoiceTaxRateLookupLookupAsync(body);
```

### C# (raw HTTP)

```csharp
using System.Text;

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

var request = new HttpRequestMessage(new HttpMethod("POST"), "/api/invoicing/invoices/tax-rate-lookup");
request.Headers.Add("api-key", "{{API_KEY}}");

request.Content = new StringContent("""
    {
      "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
    }
    """, Encoding.UTF8, "application/json");

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.InvoicingApi(client)
    body = winkpg_api.InvoiceTaxRateLookupInput.from_dict({
      "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
    })
    result = api.invoice_tax_rate_lookup_lookup(body)
```

### Python (raw HTTP)

```bash
pip install requests
```

```python
import requests

headers = {
    "api-key": "{{API_KEY}}",
    "Content-Type": "application/json",
}

body = {
  "billerId": "3fa85f64-5717-4562-b3fc-2c963f66afa6"
}

response = requests.request(
    "POST",
    "{{BASE_URL}}/api/invoicing/invoices/tax-rate-lookup",
    headers=headers,
    json=body,
)
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.