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

# Merchant Access

> Explains the base URL, credential preparation, and common request headers used by GatePay merchants.

## Base URL

`https://openplatform.gateapi.io`

If this is your first time reading the GatePay documentation, start with [Quickstart](/essentials/version/100/en/common/quickstart) and the [Merchant Access guide](/essentials/version/100/en/common/accessguide), then return to this reference section after your application, signing, and callback setup are ready.

## Integration Setup

1. Sign in to the GatePay merchant portal at [https://www.gate.com/zh/merchant#/get-started](https://www.gate.com/zh/merchant#/get-started)
2. Complete the required business information and merchant application
3. Open the application configuration page and create a new application
4. View the configured application list and obtain the application ClientId

## Generate Secrets

1. Open the developer page and generate a **Payment API Secret Key** for payment API signing and callback verification
2. Generate an **Authorization Secret Key** for authorization-related signing flows
3. Configure the callback URL so asynchronous notifications can be verified and processed

## Key Parameters

| Parameter       | Description                                                |
| --------------- | ---------------------------------------------------------- |
| Payment API key | Used for payment request signing and callback verification |
| ClientId        | Used to identify your application                          |

## Common request headers

Standard merchant APIs use the following common headers:

| Header                         | Description                                               |
| ------------------------------ | --------------------------------------------------------- |
| X-GatePay-Certificate-ClientId | Application ClientId                                      |
| X-GatePay-Timestamp            | UTC millisecond timestamp for when the request is created |
| X-GatePay-Nonce                | Request nonce                                             |
| X-GatePay-Signature            | Request signature calculated with the signing rules       |

## SDK

The latest official SDK and client repositories are maintained under [https://github.com/gate](https://github.com/gate).

Current public multi-language support includes:

* [gatepay-sdk-java](https://github.com/gate/gatepay-sdk-java)
* [gatepay-sdk-go](https://github.com/gate/gatepay-sdk-go)
* [gatepay-sdk-python](https://github.com/gate/gatepay-sdk-python)
* [gatepay-sdk-android](https://github.com/gate/gatepay-sdk-android)
* [gatepay-sdk-ios](https://github.com/gate/gatepay-sdk-ios)
* [gatepay-call-payment-sdk-android](https://github.com/gate/gatepay-call-payment-sdk-android)
* [gatepay-call-payment-sdk-iOS](https://github.com/gate/gatepay-call-payment-sdk-iOS)

For institution merchant APIs, see [Institution Headers](/api-reference/version/100/en/common/institutionalCommonHeaders).