## See the code Take a tour of the code below, and copy it into your project to get started. [block:tutorial-tile] { "backgroundColor": "#9B69FF", "emoji": "✍️", "id": "64266c35b4bf73003c637e42", "link": "https://developer.mx51.io/recipes/signature-transactions", "slug": "signature-transactions", "title": "Signature transactions" } [/block] ## Handle signature transactions Depending on the customer's bank or <>, some transactions may require them to sign a receipt. SPI handles this using a workflow that your integration must support. In this workflow, a ‘receipt to sign’ is printed, the customer signs the receipt, and the merchant accepts or rejects the signature. Sequence diagram of a signature transaction.

Sequence diagram of a signature transaction.

To handle signature transactions, you must use logic similar to the following.

1. **If** the '[TxFlowStateChanged](doc:spi-events#TxFlowStateChanged)' event contains `AwaitingSignatureCheck: true` ... 1. Print the 'receipt to sign': `e.detail.SignatureRequiredMessage._receiptToSign` 2. Display a user interface for the merchant to choose whether to accept or reject the signature ... - **Accept** — call `spi.AcceptSignature(true)` - **Reject** — call `spi.AcceptSignature(false)` For an example, see the [events code sample](doc:code-samples). After the merchant accepts/rejects the signature, the transaction will proceed. When finished, the 'TxFlowStateChanged' event will occur again and it can be [handled as a normal transaction](doc:spi-transactions). > 📘 Note: > > - Learn [what causes some transactions to require a signature](doc:spi-signature-transactions). > - Learn how to create a [UI for signature transactions](doc:spi-transactions-ui). ## Testing When using Gecko Bank, you can test the signature workflow as follows. 1. Start a transaction, e.g. by calling `spi.InitiatePurchaseTxV2(...)` 2. In Gecko Bank, click **Swipe** > **Credit** > click **Enter** without entering a PIN to trigger the signature workflow. The '[TxFlowStateChanged](doc:spi-events#TxFlowStateChanged)' event will occur containing `AwaitingSignatureCheck: true` Note that since Gecko Bank is a virtual terminal, no receipts will be printed. ## Confirm signature on terminal Some EFTPOS terminals allow the merchant to confirm the signature on the terminal. If this occurs, the '[TxFlowStateChanged](doc:spi-events#TxFlowStateChanged)' event will contain `AwaitingSignatureCheck: false` meaning that the POS does not need to handle the signature, and it can [handle the transaction normally.](doc:spi-transactions) When using Gecko Bank, you can confirm the signature as follows. 1. The ‘receipt to sign’ will display on the **Print receipt** screen. Since Gecko Bank is a virtual terminal, it does not print receipts, so click **Printed** to move on. 2. Click **Yes** to approve the customer's signature. 3. Click **Yes** if you want to print a receipt for the customer (however, Gecko Bank doesn't print receipts). 4. Click **Printed** to finish. ![Screenshots of Gecko Bank: the 'receipt to sign' screen and the 'Customer signature approved?' screen.](https://files.readme.io/bacd98b-gecko-bank-signature-transactions.png)