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

# Testing in Sandbox

> Drive every transaction lifecycle scenario end-to-end without a real card network.

The sandbox environment exposes simulation endpoints that produce authorizations, clearings, reversals, refunds, and declines on demand. Use them to test every state your integration needs to handle without waiting for a real card network event.

Simulation is available in all sandbox projects. These endpoints return an error if called in a production environment.

For the underlying status transitions and what to expect on each event, see [Lifecycle](/transactions/lifecycle).

***

## Scenario 1: Authorization and clearing

1. [Create a card](/api-reference/cards/create-card) with `type: VIRTUAL`
2. [Simulate authorization](/api-reference/simulation/simulate-authorization) with a `cardId` and `amount`
3. Confirm [`CARD_TRANSACTION_CREATED`](/api-reference/card-transaction-created) webhook received with `status: PENDING`
4. [Simulate clearing](/api-reference/simulation/simulate-clearing) with the `transactionId`
5. Confirm [`CARD_TRANSACTION_UPDATED`](/api-reference/card-transaction-updated) webhook received with `status: CLEARED`

***

## Scenario 2: Declined transaction

1. [Create a card](/api-reference/cards/create-card)
2. [Simulate decline](/api-reference/simulation/simulate-decline) with a `cardId`, `amount`, and optional `declineReason` (defaults to `INSUFFICIENT_BALANCE`)
3. Confirm [`CARD_TRANSACTION_CREATED`](/api-reference/card-transaction-created) webhook received with `status: DECLINED`

See [Decline reasons](/transactions/decline-reasons) for the full set of codes you can pass as `declineReason`.

***

## Scenario 3: Decline against a frozen card

1. [Freeze a card](/api-reference/cards/freeze-card)
2. Confirm [`CARD_STATUS_UPDATED`](/api-reference/card-status-updated) webhook received with `status: FROZEN`
3. [Simulate authorization](/api-reference/simulation/simulate-authorization) (confirm it is declined)
4. [Unfreeze a card](/api-reference/cards/unfreeze-card)
5. Confirm [`CARD_STATUS_UPDATED`](/api-reference/card-status-updated) webhook received with `status: ACTIVE`

***

## Scenario 4: Refund on a cleared transaction

1. [Create a card](/api-reference/cards/create-card)
2. [Simulate authorization](/api-reference/simulation/simulate-authorization)
3. [Simulate clearing](/api-reference/simulation/simulate-clearing) with the `transactionId`
4. [Simulate refund](/api-reference/simulation/simulate-refund) with the `transactionId`
5. Confirm [`CARD_TRANSACTION_UPDATED`](/api-reference/card-transaction-updated) webhook received

***

## Scenario 5: External authorization

<Note>
  Applies to **External** [authorization mode](/program-configuration/authorization-mode) projects only. In Managed projects, Reap decides the authorization and there is no endpoint to call.
</Note>

In an External project, simulation fires a real signed `CARD_AUTHORIZATION_REQUEST` to your registered authorization endpoint and authorizes based on the decision you return. See [The authorization request](/transactions/external-authorization/authorization-request) for the contract.

1. Register your authorization endpoint (a webhook with `mode: REQUEST`) and [create a card](/api-reference/cards/create-card)
2. [Simulate authorization](/api-reference/simulation/simulate-authorization) with a `cardId` and `amount`
3. Your endpoint receives a `CARD_AUTHORIZATION_REQUEST`; return `{ "decision": "APPROVE" }` or a decline
4. Confirm the [`CARD_TRANSACTION_CREATED`](/api-reference/card-transaction-created) webhook reflects your decision: `status: PENDING` on approve, `status: DECLINED` on decline

***

## Simulating card statuses

To force a card into a status that is otherwise hard to trigger (`BLOCKED`, `EXPIRED`), see [Simulating card statuses](/cards/overview#simulating-card-statuses-in-sandbox).