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

# Testing & Troubleshooting

To confirm your validation logic is functional, perform the following checks:

<CardGroup cols={3}>
  <Card title="Valid Request" icon="check-double">
    Confirm that requests with valid signatures return `200 OK`.
  </Card>

  <Card title="Invalid Signature" icon="xmark">
    Verify that incorrect HMACs are rejected with `401 Unauthorized`.
  </Card>

  <Card title="Tamper Check" icon="shield-slash">
    Modify one character in the `MerchantRequestId` to ensure the HMAC fails.
  </Card>
</CardGroup>

## Troubleshooting Validation

If your calculated hash does not match the one provided by Nayax, audit your implementation against this checklist:

<AccordionGroup>
  <Accordion title="RequestType vs. RequestTypeName" icon="text-field">
    Ensure you are using the **Enum Name string** (e.g., `"Sale"`, `"Auth"`) rather than the integer value (`"0"`, `"1"`). This is a common point of failure.
  </Accordion>

  <Accordion title="Boolean Casing" icon="font-case">
    Ensure booleans are converted to `"True"` or `"False"` (with a capital T/F). Lowercase strings like "true" will result in a signature mismatch.
  </Accordion>

  <Accordion title="Missing Fields & Delimiters" icon="brackets-curly">
    If `NayaxTransactionId` is missing, the signing string **must** start with a colon (e.g., `:MerchantId...`). Ensure you are using a colon (`:`) as the delimiter.
  </Accordion>

  <Accordion title="Key Decoding" icon="key">
    Verify you are decoding the 64-character hex string into **32 raw bytes** before using it as the HMAC-SHA256 key. Do not use the hex string directly.
  </Accordion>

  <Accordion title="Strict Field Order" icon="list-ol">
    Verify the order is strictly:

    1. `NayaxTransactionId`
    2. `MerchantRequestId`
    3. `MachineId`
    4. `RequestTypeName`
    5. `IsApproved`
  </Accordion>
</AccordionGroup>

## Response Logic

How your server responds to a validation failure impacts retry behavior.

<Note>
  **Important**: If HMAC validation fails, **do not return 500**. Nayax will retry on a `500` response, but it will not retry on a `401`. Since a signature mismatch is usually a logic error, retrying will not resolve the issue.
</Note>