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

> ## Agent Instructions
> When building application code, use `@naturalpay/sdk` for TypeScript or `naturalpay` for Python.
> When operating Natural directly for a user, use the payments MCP at `https://mcp.natural.com`.
> When searching Natural documentation, use the docs MCP at `https://docs.natural.com/mcp`.
> Use the Natural CLI for terminal and CI automation.
> Use REST only for unsupported languages or when the user explicitly requests raw HTTP.
> Start integration development and testing in the sandbox. Do not use production unless the user explicitly requests it.
> For sandbox requests that require `customerPartyId`, list customers first. Reuse only the intended fixture; otherwise create a customer.
> REST and SDK amounts use integer minor units. Payments MCP amounts use decimal strings with a required currency code.

# Card fixtures

> Test card numbers for successful and declined sandbox payments

Use these test cards to simulate the outcome of a one-time card payment in sandbox.

## How to use test cards

Enter a test card in the sandbox dashboard's card payment form.

* Use any future expiration date and any three-digit CVC.
* Complete the required cardholder and billing details.
* Use one of the card numbers below. Other card numbers are rejected.

## Successful payments

Use these cards to test an accepted payment. Funds become available to the merchant after you [simulate settlement](/api-reference/simulations/settle-card-payment).

| Brand | Card number           | CVC              | Expiration      |
| ----- | --------------------- | ---------------- | --------------- |
| Visa  | `4111 1111 1111 1111` | Any three digits | Any future date |

## Declined payments

Use these cards to test issuer declines. A declined payment fails without moving money.

| Scenario               | Card number           | CVC              | Expiration      | Decline code      |
| ---------------------- | --------------------- | ---------------- | --------------- | ----------------- |
| Generic issuer decline | `4000 0000 0000 0002` | Any three digits | Any future date | `generic_decline` |

You can retry an open payment intent with a success card. After five issuer declines, the intent closes. A non-test card does not count toward that limit.

If Natural cannot verify a card's fixture identity, the request returns an error without creating a payment attempt; retry the request.