Authorization Reversals

Simulate reversing an open authorization, either fully (releasing the entire hold) or partially (reducing the authorized amount).

Beta Feature

The Transaction Simulations feature is currently in beta. API endpoints and behavior may change as we continue to refine the product. Simulation endpoints are available in development environments only — production returns 404 Not Found.

Simulate reversing an open authorization — for example, when a merchant cancels a transaction before settlement or reduces the authorized amount. Reversals release the hold on the cardholder’s balance without creating a posted transaction.

Use this to test how your integration handles authorization reversals, including partial reversals where only a portion of the original hold is released.

Full vs. partial reversal

• Full reversal — Omit newAmount to release the entire hold. The transaction amount becomes 0.
• Partial reversal — Provide newAmount to specify the remaining authorized amount. The difference is released back to the cardholder’s available balance.

Endpoint

POST /v1/simulate/transactions/:transactionId/reverse

Path parameters

Parameter	Type	Required	Description
transactionId	string (UUID)	Yes	The ID of an existing authorized transaction to reverse.

Headers

Header	Type	Required	Description
Api-Key	string	Yes	Your tenant API key. The tenant scope is resolved from this key.
Content-Type	application/json	Yes	—

Body

Field	Type	Required	Description
newAmount	integer	No	The remaining authorized amount in cents after the reversal. Omit for a full reversal. Must be a non-negative integer.

Full reversal (release entire hold)

{}

Partial reversal (reduce authorized amount to $4.00)

{
  "newAmount": 400
}

Response

A successful response returns the transaction ID and status.

200 OK

{
  "transactionId": "f3a1c92e-1b3d-4d1e-bb22-12c0a4d5b8f9",
  "status": "authorized"
}

Field	Type	Description
transactionId	string (UUID)	The transaction ID.
status	string	The transaction status: authorized.

Errors

Status	When
400 Bad Request	Invalid body (negative newAmount), transaction is already settled, transaction is already closed, no card associated with the transaction, or the card has no processor ID.
404 Not Found	Endpoint not available in production, simulations are not enabled for your tenant, or the transaction does not exist.
500 Internal Server Error	Unhandled error during simulation.

Behavior notes

• Transaction must be an open authorization. You can only reverse authorizations that have not yet settled or closed.
• Reversals release holds, not funds. Unlike refunds, reversals do not move posted funds — they release authorization holds.
• Triggers webhooks. The reversal fires the same webhooks as a real authorization reversal.

Example

Full reversal

curl -X POST https://api-dev.rain.xyz/v1/simulate/transactions/f3a1c92e-1b3d-4d1e-bb22-12c0a4d5b8f9/reverse \
  -H "Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{}'

Partial reversal

curl -X POST https://api-dev.rain.xyz/v1/simulate/transactions/f3a1c92e-1b3d-4d1e-bb22-12c0a4d5b8f9/reverse \
  -H "Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "newAmount": 400
  }'