> For the complete documentation index, see [llms.txt](https://docs.a-pay.one/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.a-pay.one/api-documentation.md).

# API Documentation

- [Start Integration](https://docs.a-pay.one/api-documentation/start-integration.md)
- [Payment Systems information](https://docs.a-pay.one/api-documentation/payment-systems-information.md)
- [Getting data about PS](https://docs.a-pay.one/api-documentation/payment-systems-information/getting-data-about-ps.md)
- [Getting payment system balances](https://docs.a-pay.one/api-documentation/payment-systems-information/getting-payment-system-balances.md)
- [Payment Page Integration](https://docs.a-pay.one/api-documentation/payment-page-integration.md)
- [Payment Gateway](https://docs.a-pay.one/api-documentation/payment-page-integration/payment-gateway.md)
- [API Integration](https://docs.a-pay.one/api-documentation/api-integration.md)
- [Deposit](https://docs.a-pay.one/api-documentation/api-integration/deposit.md)
- [Request to create a deposit](https://docs.a-pay.one/api-documentation/api-integration/deposit/request-to-create-a-deposit.md)
- [Deposit Activation](https://docs.a-pay.one/api-documentation/api-integration/deposit/deposit-activation.md)
- [Deposit information](https://docs.a-pay.one/api-documentation/api-integration/deposit/deposit-information.md)
- [Withdrawal](https://docs.a-pay.one/api-documentation/api-integration/withdrawal.md)
- [Lost transaction](https://docs.a-pay.one/api-documentation/api-integration/lost-transaction.md)
- [Create lost transaction](https://docs.a-pay.one/api-documentation/api-integration/lost-transaction/create-lost-transaction.md): This request will allow you to create transaction search requests in our system.
- [Lost transaction information](https://docs.a-pay.one/api-documentation/api-integration/lost-transaction/lost-transaction-information.md): This request will allow you to find out the status of the transaction search
- [Postback](https://docs.a-pay.one/api-documentation/postback.md): Communication takes place with the help of postback requests (postbacks). After each Client request for input or output, a postback is sent to the Client with the result of the operation.
- [Settlement](https://docs.a-pay.one/api-documentation/settlement.md)
- [Report](https://docs.a-pay.one/api-documentation/report.md): Use A-pay Reports API to create transaction reports in CSV format for payment checks and daily operations.
- [Errors](https://docs.a-pay.one/api-documentation/errors.md)