Transaction

A Transaction is a financial record created when a payment is attempted or a related operation is processed. It answers what happened to the money.

A Transaction can include:

• The amount and currency
• Its processing status
• The payment type and entry mode
• SumUp and merchant-provided identifiers
• Card, device, payout, refund, and other event details where applicable

Unlike a Sale, a Transaction does not describe the full basket or commercial context. Unlike a Checkout, it is not an instruction to collect a payment: it records the result of processing one.

Transaction Lifecycle

stateDiagram-v2
    [*] --> PENDING: Payment attempt created
    PENDING --> SUCCESSFUL: Payment completes
    PENDING --> FAILED: Payment fails
    PENDING --> CANCELLED: Payment is cancelled
    SUCCESSFUL --> REFUNDED: Full or partial refund

The Transaction status is separate from the Checkout status. For example, a Checkout can be PENDING while a redirect-based payment is still being completed, and its linked Transaction can also have its own PENDING state.

Transactions in the Public APIs

The Transactions API supports the post-payment lifecycle:

• Retrieve a transaction by its SumUp ID, transaction code, foreign transaction ID, or client transaction ID
• List transactions for a merchant and filter the history by status, payment type, entry mode, or transaction type
• Refund a transaction in full or partially

Transaction history can include payments, refunds, and chargebacks. A full Transaction resource can also contain events related to refunds, chargebacks, payouts, and payout deductions.

Relationship to a Sale and Checkout

A typical online flow starts with a Sale or order in your system. You create a Checkout for the amount to collect, then process it. The payment attempt creates a Transaction, and the Checkout response links to it through fields such as transaction_id, transaction_code, and transactions.

Not every Transaction originates from the online Checkouts API. In-person payments initiated through a reader or mobile SDK also produce Transactions. Use stable merchant-provided references and store SumUp identifiers so you can reconcile each Transaction with the correct Sale.