> For the complete documentation index, see [llms.txt](https://apidocs.onekeypayments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://apidocs.onekeypayments.com/api-reference/know-your-customer-api.md).

# Know your customer API

- [Security aspects](https://apidocs.onekeypayments.com/api-reference/know-your-customer-api/security-aspects.md)
- [Calculating the Signature](https://apidocs.onekeypayments.com/api-reference/know-your-customer-api/security-aspects/calculating-the-signature.md): Learn how to calculate and send the Signature header value to verify requests integrity
- [Get customer information](https://apidocs.onekeypayments.com/api-reference/know-your-customer-api/get-customer-information.md)
- [API Codes](https://apidocs.onekeypayments.com/api-reference/know-your-customer-api/get-customer-information/api-codes.md)