# Communication Protocols

Merchants accessing the PayerMax service and calling the API must follow the following rules:
|         type          |                 desc                                                                                    |
|-------------------|-----------------------------------------------------------------------------------------------------|
| Transmission Method | In order to ensure transaction security, HTTPS transmission is adopted, and TLS version should not be lower than 1.2. For details, please refer to [TLS Upgrade Instructions](https://docs.payermax.com/en/202606-version/developer/tls-upgrade.md) |
| Submission Method  | Submit by POST method                                                                                |
| Data Format        | Submit and return data in application/json format                                                    |
| Character Encoding | Uniformly use UTF-8 character encoding                                                              |
| Signature Algorithm| SHA256WithRSA                                                                                        |
| Signature Requirements | Both request and received data need to verify the signature. For details, please refer to [Signature Rules](https://docs.payermax.com/en/202606-version/developer/signature-rules.md) |
| Process Logic      | First refer to the return of the protocol field, then refer to the code in the response message, and finally refer to the transaction status               |