> ## 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. # Overview > This guide introduces the prerequisites, base configuration, service endpoints, app creation, key management, and supported payment networks and currencies for GatePay external APIs. ## Recommended Reading Order If this is your first integration, the recommended reading order is: 1. [Quickstart](/essentials/version/100/en/common/quickstart) 2. [Merchant Access](/essentials/version/100/en/common/accessguide) 3. [Authentication](/essentials/version/100/en/common/authentication) 4. [Notification](/essentials/version/100/en/common/notification) 5. The guide and API Reference for your target product flow ## Merchant Onboarding and App Configuration ### Base URL | Component | Value | | ---------------- | --------------------------------- | | Service Base URL | `https://openplatform.gateapi.io` | All API paths in this documentation must be combined with the base URL to form the full request URL. ### Create and Configure an App Follow these steps to set up your application in the GatePay Merchant Portal: | Step | Action | | ---- | ------------------------------------------------------------------------------------------- | | 1 | Log in to the GatePay Merchant Portal and complete merchant registration and initial setup. | | 2 | Fill in the required business information and submit your merchant application. | | 3 | Navigate to the app configuration page and create or configure a new application. | | 4 | Retrieve your `ClientId` from the application list. | | 5 | Configure the callback URL as needed to receive asynchronous notifications. | ### Configuration Credentials After completing app configuration, you will receive the following credentials: | Credential | Description | | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `ClientId` | Unique identifier for your application. Used in all API requests via the `X-GatePay-Certificate-ClientId` header (see [Authentication and Security](/essentials/version/100/en/common/authentication) for details). | | Payment API Secret | Server-side signing key for payment-related API requests and signature verification. | | Authorization Secret | Server-side signing key for authorization API requests and signature verification (used only by authorization APIs). | | Callback URL | Endpoint configured to receive asynchronous payment notifications. | **Important:** Any API that uses asynchronous notifications requires a valid callback URL to be configured; otherwise, notifications cannot be delivered. For details on how to verify incoming callbacks, see [Authentication and Security](/essentials/version/100/en/common/authentication). ### Common Request Headers For most non-institution APIs, requests commonly use the following headers: | Header | Description | | -------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `X-GatePay-Certificate-ClientId` | Application identity | | `X-GatePay-Timestamp` | UTC timestamp in milliseconds | | `X-GatePay-Nonce` | Random nonce | | `X-GatePay-Signature` | Request signature generated from the signing rules | | `X-GatePay-On-Behalf-Of` | Institution-only delegated header. It is required on every institution API except `POST /merchant/open/institution/v1/accounts/create`, `GET /merchant/open/institution/v1/accounts/query`, and `GET /merchant/open/institution/v1/accounts/list`. | For full header, signing, and verification details, refer to the [Authentication and Security](/essentials/version/100/en/common/authentication) guide. ### SDK Support The latest official SDK and client repositories are maintained under the Gate GitHub organization: [https://github.com/gate](https://github.com/gate) The currently public multi-language SDK / client resources include: | Repository | Language | Description | | ---------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------- | | `gatepay-sdk-java` | Java | GatePay Java repository, [repository](https://github.com/gate/gatepay-sdk-java) | | `gatepay-sdk-go` | Go | GatePay Go repository, [repository](https://github.com/gate/gatepay-sdk-go) | | `gatepay-sdk-python` | Python | GatePay Python SDK repository, [repository](https://github.com/gate/gatepay-sdk-python) | | `gatepay-sdk-android` | Android | GatePay Android SDK repository, [repository](https://github.com/gate/gatepay-sdk-android) | | `gatepay-sdk-ios` | iOS | GatePay iOS SDK repository, [repository](https://github.com/gate/gatepay-sdk-ios) | | `gatepay-call-payment-sdk-android` | Android Call Payment | GatePay Android Call Payment SDK repository, [repository](https://github.com/gate/gatepay-call-payment-sdk-android) | | `gatepay-call-payment-sdk-iOS` | iOS Call Payment | GatePay iOS Call Payment SDK repository, [repository](https://github.com/gate/gatepay-call-payment-sdk-iOS) | Use the Gate GitHub organization page as the source of truth for the latest repository list. If a specific flow does not yet have a ready-made SDK wrapper, you can still integrate directly through the REST APIs documented here. ## Supported Payment Networks and Currencies ### Blockchain Networks and Supported Cryptocurrencies The following networks and tokens are supported for address-based payments: | Blockchain Network | Supported Currencies | | ------------------------ | -------------------------- | | Ethereum / ERC20 | ETH, POL, USDC, USDT, USDS | | Polygon | POL, USDC, USDT | | Arbitrum One / ERC20 | USDC, USDT | | BNB Smart Chain / BEP20 | BNB, USDT | | Solana | SOL, USDC, USDT | | Tron / TRC20 | TRX, USDT | | Base | USDC | | Ton | USDT | | Bitcoin BRC20 / Ordinals | BTC | ### Supported Currencies for Other Payment Channels The following cryptocurrencies and digital assets are supported across other payment methods: BTC, USDT, USD, GT, ETH, EOS, DOGE, DOT, SHIB, LTC, ADA, BCH, FIL, ZEC, BNB, UNI, XRP, STEPG, SUPE, LION, FROG ## Next Steps * If you want to run the first end-to-end flow quickly, start with [Quickstart](/essentials/version/100/en/common/quickstart) * For authentication details and request signing, see [Authentication and Security](/essentials/version/100/en/common/authentication) * For payment API integration, refer to your specific payment flow documentation * For error handling and best practices, consult the error codes and troubleshooting guide