# POST /api/v1/credit/programs/{program_id}/mcc-allowlist/preview

> Preview an MCC allow list

- **Tag:** credit
- **Operation ID:** `credit_mcc_allowlist_preview`

## Description

Builds the allow-list table from one source: an uploaded card export (`multipart/form-data` with a `file` part, CSV or JSON), the program's own settlements over `window_days` (`source: settlements`), or a curated list (`source: preset`, `preset: ad_spend`). Every source returns the same table: per MCC its description, transactions, spend, the Ramp category it reaches the issuer as or `unmapped`, and whether it is suggested. Changes nothing. Operator action.

## Authentication

Bearer token in `Authorization` header.
Required header: `x-business-id: <business uuid>`.

## Parameters

- `program_id` (path, string, required)

## Request body

- `source` (string · required) (one of: settlements, preset) — `settlements` builds the table from this program's own posted settlements; `preset` from a curated list.
- `window_days` (integer) — For `settlements`: how many days back from today to read. Ignored for a preset.
- `preset` (string) — For `preset`: which curated list. Required with `preset`.
- `min_count` (integer) — An MCC is suggested only when it was seen at least this many times (and maps to a Ramp category). Every preset code is suggested.

## Responses

### 201 — Successful Response

Schema: `SuccessEnvelope_MccAllowlistPreviewResponse_`

- `success` (boolean)
- `message` (string)
- `code` (string)
- `data` (MccAllowlistPreviewResponse)

### 400 — Bad Request - Invalid input

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 401 — Unauthorized - Missing or expired token, an MCP OAuth token used against the REST API, or no access to this business

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 403 — Forbidden - Insufficient permissions

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 404 — Not Found - Resource does not exist

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

### 422 — Validation Error

Schema: `ErrorResponse`

- `error` (string · required) — Error category: `validation_error`, `unauthorized`, `forbidden`, `not_found`, `conflict`, `rate_limited`, `server_error`, or `service_unavailable`.
- `message` (string · required) — Human-readable explanation, safe to show to end users.
- `code` (string · required) — Stable machine-readable code in `CATEGORY_NNN` form (e.g. `NOT_FOUND_006`, `AUTH_010`, `GEN_002`).
- `request_id` (string) — Correlation id for support requests. Echoes the `x-request-id` request header when one was supplied.
- `errors` (object) — Field-level validation messages keyed by field name. Present on 400/422 validation failures only.

## Code samples

### cURL

```bash
curl -X POST 'https://api.ondayzero.com/api/v1/credit/programs/{program_id}/mcc-allowlist/preview' \
  -H 'Authorization: Bearer dz_your_token' \
  -H 'x-business-id: YOUR_BUSINESS_ID' \
  -H 'Content-Type: application/json' \
  -d '{
  "source": "settlements"
}'
```

### JavaScript

```javascript
const response = await fetch('https://api.ondayzero.com/api/v1/credit/programs/{program_id}/mcc-allowlist/preview', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer dz_your_token',
    'x-business-id': 'YOUR_BUSINESS_ID',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "source": "settlements"
}),
});
const data = await response.json();
```

### Python

```python
import httpx

headers = {
    "Authorization": "Bearer dz_your_token",
    "x-business-id": "YOUR_BUSINESS_ID",
}

payload = {'source': 'settlements'}

response = httpx.post("https://api.ondayzero.com/api/v1/credit/programs/{program_id}/mcc-allowlist/preview", headers=headers, json=payload)
data = response.json()
```

## See also

- HTML version: https://www.ondayzero.com/docs/reference/credit/credit-mcc-allowlist-preview
- OpenAPI slice: https://www.ondayzero.com/docs/reference/credit/credit-mcc-allowlist-preview/openapi.json
- Other endpoints in **credit**: https://www.ondayzero.com/docs/reference/credit (markdown bundle: https://www.ondayzero.com/docs/reference/credit.md, OpenAPI: https://www.ondayzero.com/docs/reference/credit/openapi.json)
- Endpoint catalog: https://www.ondayzero.com/docs/reference/index.md