> ## 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. # 试算商户手续费 > 本接口用于根据商户信息、订单金额等参数，试算该笔交易的手续费金额。仅限Gate Pay商户调用。 ## 概述 本页说明 `POST /payment/open/institution/payClearing/clearing/previewMerchantFee` 接口。完整的请求参数、响应结构与示例由上方关联的 OpenAPI 定义渲染。 ## 说明 * 认证方式使用 GatePay 标准签名请求头。 * 本页展示同一接口的机构路径版本。 * 除创建子账户、查询子账户详情、分页查询子账户外，机构侧请求需携带 `X-GatePay-On-Behalf-Of`。 * 通用签名规则请参见 [/api-reference/version/100/cn/common/securityAndSignature](/api-reference/version/100/cn/common/securityAndSignature)。 ## OpenAPI ````yaml api-reference/version/100/cn/openapi/institution/preview-merchant-fee-openapi.json POST /payment/open/institution/payClearing/clearing/previewMerchantFee openapi: 3.1.0 info: title: GatePay 机构商户手续费 API description: GatePay 支付平台 API 接口文档 - 试算商户手续费 license: name: MIT version: 1.0.0 servers: - url: https://openplatform.gateapi.io security: [] paths: /payment/open/institution/payClearing/clearing/previewMerchantFee: post: summary: 试算商户手续费 description: 本接口用于根据商户信息、订单金额等参数，试算该笔交易的手续费金额。仅限Gate Pay商户调用。 parameters: - $ref: '#/components/parameters/X-GatePay-Certificate-ClientId' - $ref: '#/components/parameters/X-GatePay-Signature' - $ref: '#/components/parameters/X-GatePay-Timestamp' - $ref: '#/components/parameters/X-GatePay-Nonce' - $ref: '#/components/parameters/X-GatePay-On-Behalf-Of' requestBody: description: 试算商户手续费请求参数 content: application/json: schema: $ref: '#/components/schemas/PreviewMerchantFeeRequest' examples: basicExample: summary: 基础示例 value: orderCurrency: USDT accessMode: 0 scenario: 0 orderAmount: '100.00' required: true responses: '200': description: 试算成功 content: application/json: schema: $ref: '#/components/schemas/PreviewMerchantFeeResponse' examples: successResponse: summary: 成功响应 value: status: success code: '000000' errorMessage: '' data: merchantId: '123456789' merchantType: 1 accessMode: 0 orderCurrency: USDT orderAmount: 100 orderFee: 2.5 '400': description: 请求参数错误 content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: invalidParams: summary: 无效请求参数 value: status: error code: '400001' errorMessage: 无效请求参数 data: null invalidSignature: summary: 无效签名 value: status: error code: '400002' errorMessage: 无效签名 data: null invalidApiKey: summary: API身份秘钥不存在或无效 value: status: error code: '400004' errorMessage: API身份秘钥不存在或无效 data: null invalidClientId: summary: 客户端 ID 无效 value: status: error code: '400005' errorMessage: INVALID_CLIENT_ID/clientid错误 data: null unsupportedMediaType: summary: 不支持的media type value: status: error code: '400007' errorMessage: 不支持的media type data: null '500': description: 服务端错误 content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: feeServiceError: summary: 调用费率服务试算接口失败 value: status: error code: '503011007' errorMessage: 调用费率服务试算接口失败 data: null feeConfigEmpty: summary: 商户费率配置为空 value: status: error code: '503011008' errorMessage: 商户费率配置为空 data: null unknownError: summary: 未知错误 value: status: error code: '503010999' errorMessage: 未知错误 data: null components: parameters: X-GatePay-Certificate-ClientId: name: X-GatePay-Certificate-ClientId in: header required: true description: 商户ID schema: type: string example: mZ96D37oKk-HrWJc X-GatePay-Signature: name: X-GatePay-Signature in: header required: true description: 签名 schema: type: string example: >- 601d560c54d53412aca5901256f101e7078b5779f61f30bedfe9a5f0b92f049589952a151ea477371e4a99ac0e1c3cc8dec62654b3c6a1794ef981efe19232bc X-GatePay-Timestamp: name: X-GatePay-Timestamp in: header required: true description: 时间戳（毫秒） schema: type: string example: '1726027137585' X-GatePay-Nonce: name: X-GatePay-Nonce in: header required: true description: 随机数 schema: type: string example: '2290830087' X-GatePay-On-Behalf-Of: name: X-GatePay-On-Behalf-Of in: header required: true schema: type: string description: >- 必填代理归属请求头。请填写本次请求的发起方账户 ID；在机构代理商户 API 中通常填写目标子账户 ID，在机构代扣与划转接口中可填写机构账户 ID 或子账户 ID。 schemas: PreviewMerchantFeeRequest: type: object required: - orderCurrency - accessMode - scenario - orderAmount properties: orderCurrency: type: string description: 订单币种，如：USDT、USDC等 example: USDT accessMode: type: integer description: 接入模式：0=中心化支付，1=Web3支付 enum: - 0 - 1 example: 0 scenario: type: integer description: 交易类型（场景）：0=收款 enum: - 0 example: 0 orderAmount: type: string format: decimal description: 订单金额，必须大于等于0 example: '100.00' PreviewMerchantFeeResponse: type: object properties: status: type: string description: 响应状态：success/error enum: - success - error example: success code: type: string description: 响应码，000000表示成功 example: '000000' errorMessage: type: string description: 错误信息，成功时为空 example: '' data: $ref: '#/components/schemas/PreviewMerchantFeeData' ErrorResponse: type: object properties: status: type: string description: 响应状态 enum: - error example: error code: type: string description: 错误码 example: '400001' errorMessage: type: string description: 错误信息 example: 无效请求参数 data: type: 'null' description: 错误时为空 PreviewMerchantFeeData: type: object properties: merchantId: type: string description: 商户ID example: '123456789' merchantType: type: integer description: 商户类型：0=普通商户，1=代理商 enum: - 0 - 1 example: 1 accessMode: type: integer description: 接入模式：0=中心化支付，1=Web3支付 enum: - 0 - 1 example: 0 orderCurrency: type: string description: 订单币种 example: USDT orderAmount: type: number format: decimal description: 订单金额 example: 100 orderFee: type: number format: decimal description: 计算出的手续费 example: 2.5 ````