Transactions

Credit/refund a transaction

Refunds or credits a prior transaction. Send amount_cents for a partial refund; omit it to refund the full amount. Partial refunds accumulate in the source transaction’s credited_amount_cents. Creates a refund/ general_credit transaction linked via parent_transaction_id and returns it with 201. Pass an Idempotency-Key header to make retries safe. Returns 404 when the transaction is not found, 409 on an in-flight duplicate key, and 422 when the requested amount exceeds the refundable balance or the transaction cannot be refunded.

POST

api

payment

v2026-04

transactions

{id}

credit

curl --request POST \
  --url https://api.fluid.app/api/payment/v2026-04/transactions/{id}/credit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{}'

{
  "data": {
    "id": "<string>",
    "amount_cents": 123,
    "currency_code": "<string>",
    "processing_fee_cents": 123,
    "credited_amount_cents": 123,
    "retain_on_success": true,
    "metadata": {},
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "gateway_id": "<string>",
    "payment_method_id": "<string>",
    "card_network": "<string>",
    "parent_transaction_id": "<string>",
    "payment_source": "<string>",
    "gateway_transaction_id": "<string>",
    "reference_token": "<string>",
    "description": "<string>",
    "platform_fee_cents": 123
  },
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  },
  "status": "<string>"
}

{
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

Authorizations

Authorization

string

header

required

API key (fp_live_/fp_test_) or JWT bearer token

Headers

Idempotency-Key

string

Optional client-generated key (UUID recommended) used to deduplicate retries. The first request with a given key executes normally; a retry with the same key replays that first response with X-Idempotent-Replayed: true for up to 24 hours. A concurrent retry while the first request is still in flight returns 409.

The response cache is keyed on the authenticated merchant and this key ONLY — not on the operation, path, or request body. Use a fresh, unique key per logical request: reusing one key across different operations (for example a purchase and then a capture) replays the first operation's cached status and body instead of performing the second.

Maximum string length: 255

Path Parameters

string

required

Transaction slug (transaction to refund)

Body

application/json

transaction

object

Show child attributes

Response

Credit created

data

object

required

Show child attributes

meta

object

required

Show child attributes

Void an authorization

Get merchant payment configuration

curl --request POST \
  --url https://api.fluid.app/api/payment/v2026-04/transactions/{id}/credit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{}'

{
  "data": {
    "id": "<string>",
    "amount_cents": 123,
    "currency_code": "<string>",
    "processing_fee_cents": 123,
    "credited_amount_cents": 123,
    "retain_on_success": true,
    "metadata": {},
    "created_at": "2023-11-07T05:31:56Z",
    "updated_at": "2023-11-07T05:31:56Z",
    "gateway_id": "<string>",
    "payment_method_id": "<string>",
    "card_network": "<string>",
    "parent_transaction_id": "<string>",
    "payment_source": "<string>",
    "gateway_transaction_id": "<string>",
    "reference_token": "<string>",
    "description": "<string>",
    "platform_fee_cents": 123
  },
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  },
  "status": "<string>"
}

{
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

{
  "status": "error",
  "message": "<string>",
  "meta": {
    "request_id": "<string>",
    "timestamp": "2023-11-07T05:31:56Z"
  }
}

Overview

Task guides

Endpoints

Auth endpoints

Checkout endpoints

Public SDK endpoints

Payment gateway endpoints

Cart payment endpoints

Commerce endpoints

Webhooks endpoints

Credit/refund a transaction

Authorizations

Headers

Path Parameters

Body

Response