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

# Confirm transactions using the Hanko FIDO UAF Client

> Bind a transaction to the authentication challenge and confirm it on-device with the Hanko FIDO UAF Client.

The process for confirming transactions with the Hanko FIDO UAF Client is essentially the same as for the
regular [authentication](/hanko-authenticator/quickstart/uaf-client-authentication) process.

The main difference between the two is that when *initializing* the request you need to supply a request body with an
additional `transaction` attribute. Its value is a transaction text that becomes part of the challenge issued by the
FIDO server and hence the signature created in the course of the authentication process.

<CodeGroup>
  ```bash httpie theme={null}
  http POST {API_URL}/v1/uaf/requests \
   'Authorization:secret pasteYourApiKeySecretHere' \
   'operation=AUTH' \
   'username=example@example.com' \
   'userId=exampleId' \
   'transaction=Transfer $100 to Mike?'
  ```

  ```bash cURL theme={null}
  curl -X POST "{API_URL}/v1/uaf/requests" \
  -H 'Authorization:secret pasteYourApiKeyHere' \
  -H 'Content-Type: application/json' \
  -d '{"operation": "AUTH", "username":"example@example.com", "userId":"exampleId", "transaction": "Transfer $100 to Mike?" }'
  ```
</CodeGroup>

Once the request has been initiated, pass it to the Hanko FIDO UAF Client and send the response back to the Hanko API exactly as described in the [authentication](/hanko-authenticator/quickstart/uaf-client-authentication) guide.