# Fail a payment

> Sandbox only. Fails one payment, with the reason you choose.

```
POST https://api.sandbox.stridehq.ai/v1/test_helpers/payments/{id}/fail
```

Not available yet: this endpoint is planned.

Scope: `payment_runs:prepare`

## Path parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `id` | string | Yes | The payment's id. |

## Body

| Name | Type | Required | Description |
|---|---|---|---|
| `failure_reason` | string | No |  |

## Responses

- **200**: The payment, `failed`.
- **404**: `resource_not_found`: no such object in your organisation.

```json
{
  "id": "pay_7c9e1a3b5d7f4a2c8e0b1d3f5a7c9e1b",
  "object": "payment",
  "payment_run_id": "run_3e5a7c9b1d2f4a6c8e0b2d4f6a8c0e1d",
  "creator_id": "cre_8f3a2c1d9b7e4f60a1b2c3d4e5f60718",
  "invoice_id": "inv_4b1e7d2a9c3f4e5d8a6b0c1d2e3f4a5b",
  "amount": 250000,
  "currency": "GBP",
  "funding_amount": 250000,
  "funding_currency": "GBP",
  "fx_rate": null,
  "status": "paid",
  "failure_reason": null,
  "failure_message": null,
  "paid_at": "2026-10-30T10:12:00Z",
  "bank_account_last4": "4821",
  "created_at": "2026-10-29T09:00:00Z"
}
```