> ## Documentation Index > Fetch the complete documentation index at: https://docs.cryptoprocessing.com/llms.txt > Use this file to discover all available pages before exploring further. # Get a fixed exchange quote > Get a fixed exchange quote for a specific amount, which can then be used with [/exchange/fixed](/api-reference/endpoints/exchange-fixed). ## OpenAPI ````yaml POST /exchange/calculate openapi: 3.0.0 info: title: Merchant Backend V2 version: '1.0' description: Documentation for merchant backend processing endpoints servers: - url: https://app.cryptoprocessing.com/api/v2 security: - xProcessingKey: [] tags: - name: Status - name: Balance - name: Currencies - name: Deposit addresses - name: Withdrawal - name: Exchange - name: Invoices - name: Transactions paths: /exchange/calculate: post: tags: - Exchange summary: Get an exchange quote description: >- Get a fixed exchange quote for a specific amount, which can then be used with [/exchange/fixed](/api-reference/endpoints/exchange-fixed). operationId: post-exchange-calculate parameters: - $ref: '#/components/parameters/XProcessingSignatureHeader' requestBody: content: application/json: schema: type: object properties: sender_currency: type: string description: >- Currency to exchange from. For a list of all available currencies, see [API currency codes](/api-reference/currency-codes). receiver_currency: type: string description: >- Currency to exchange to. For a list of all available currencies, see [API currency codes](/api-reference/currency-codes). sender_amount: description: >- Amount to send. You must include either this parameter or `receiver_amount`. type: number receiver_amount: description: >- Amount to receive. You must include either this parameter or `sender_amount`. type: number required: - sender_currency - receiver_currency examples: sender_amount: value: sender_currency: BTC receiver_currency: EUR sender_amount: 0.02 receiver_amount: value: sender_currency: BTC receiver_currency: EUR receiver_amount: 100 description: '' responses: '200': description: OK content: application/json: schema: type: object properties: data: type: object properties: sender_currency: type: string description: The currency being exchanged from. sender_amount: type: string description: >- If `sender_amount` was provided in the request, this is the requested send amount. If `receiver_amount` was provided, this is the calculated amount to send. receiver_currency: type: string description: The currency being exchanged to. receiver_amount: type: string description: >- If `receiver_amount` was provided in the request, this is the requested receive amount. If `sender_amount` was provided, this is the calculated amount to receive. fee_currency: type: string description: The currency in which the exchange fee is charged. fee_amount: type: string description: >- The exchange fee amount. If the fee is charged in the sender currency, the total debited amount is `sender_amount + fee_amount`. price: type: string description: >- The quoted exchange rate, expressed as units of `receiver_currency` for 1 unit of `sender_currency`. ts_fixed: type: integer description: >- Unix timestamp, in seconds, when the quote rate was fixed. format: int64 ts_release: type: integer format: int64 description: Unix timestamp, in seconds, when the quote expires. fix_period: type: integer format: int32 description: >- How long the fixed quote remains valid, in seconds. After this period, request a new quote. examples: sender_amount: value: data: sender_currency: BTC sender_amount: '0.02000000' receiver_currency: EUR receiver_amount: '1546.28528889' fee_currency: BTC fee_amount: '0.00100000' price: '77314.26444450' ts_fixed: 1775172819 ts_release: 1775172879 fix_period: 60 receiver_amount: value: data: sender_currency: BTC sender_amount: '0.00129342' receiver_currency: EUR receiver_amount: '100.00000000' fee_currency: BTC fee_amount: '0.00006467' price: '77314.40676655' ts_fixed: 1775172897 ts_release: 1775172957 fix_period: 60 '400': description: Bad Request. content: text/html: schema: $ref: '#/components/schemas/ValidationOrMalformedJson' examples: Invalid sender currency: summary: Sender currency not supported value: errors: sender_currency: Currency not supported Invalid receiver currency: summary: Receiver currency not supported value: errors: receiver_currency: Currency not supported Invalid amount: summary: Amount below minimum or invalid format value: errors: sender_amount: Invalid amount format Same currency pair: summary: Cannot exchange same currency value: errors: receiver_currency: Cannot exchange currency to itself Missing fields: summary: Required fields missing value: errors: receiver_currency: The receiver currency field is required. receiver_amount: >- The receiver amount field is required when the sender amount field is not presented. Malformed JSON: summary: Invalid JSON body value: error: Bad content format code: bad_content_format '403': $ref: '#/components/responses/HeaderAuthorization' components: parameters: XProcessingSignatureHeader: name: X-Processing-Signature in: header required: true description: >- Hex-encoded HMAC-SHA512 signature of the request body, [generated using your secret key](/api-reference/authentication). schema: type: string schemas: ValidationOrMalformedJson: oneOf: - type: object title: ValidationError description: One or more request parameters failed validation. properties: errors: type: object additionalProperties: type: string - type: object title: MalformedJson description: >- The request body is not valid JSON or the Content-Type header is not set to `application/json`. properties: error: type: string code: type: string responses: HeaderAuthorization: description: | Forbidden content: application/json: schema: type: object properties: error: type: string description: Human-readable error message. code: type: string description: Error code. description: >- Invalid or missing headers. Refer to [Errors](/api-reference/errors#403) for troubleshooting steps. examples: Bad signature header: value: error: Bad signature header code: bad_header_signature No signature header: value: error: No signature header code: required_header_signature Bad key header: value: error: Bad key header code: bad_header_key No key header: value: error: No key header code: required_header_key securitySchemes: xProcessingKey: type: apiKey description: Your [API key](/integration-guide/get-your-api-key). in: header name: X-Processing-Key ````