> ## Documentation Index > Fetch the complete documentation index at: https://docs.zapyd.com/llms.txt > Use this file to discover all available pages before exploring further. # Fetch Rate > Returns the current fiat-to-crypto rate for payins. Add the Zapyd "Fetch Rate" call (`GET /pis/api/v1/payin/fetch-rate`) to my backend. Returns the current fiat-to-crypto rate for payins. * Sandbox: `GET https://sandbox.zapyd.com/pis/api/v1/payin/fetch-rate` * Production: `GET https://api.zapyd.com/pis/api/v1/payin/fetch-rate` Query parameters: * `asset` (string, required): Crypto asset code, e.g. USDT or USDC. * `fiat` (string, required): Fiat currency code, e.g. INR. * `network` (string, required): Blockchain network, for example tron or polygon. See supported\_networks in Fetch Configuration. * `payment_method` (string, optional): Payin payment method. Required for USD. * `sending_amount` (string, optional): Fiat amount the customer will pay. Required for USD, where it is checked against per-transaction limits. Success: HTTP 200, `{status: true, message, data}`. `data`: `asset`, `fiat`, `rate`, `network`, `fees` (Banking fee disclosure per payment method. Informational only; it is not applied to `rate`). Errors (`{status: false, message, err_code, errors}`): * 500 `Internal Server Error` Every endpoint can also return 401 `AUTH_*` (signature, timestamp or key: fix, don't retry), and 429 or 5xx (retry with backoff). Rules: * An indicative rate to show before the user commits. Only a quotation locks the rate. * For USD, `payment_method` and `sending_amount` are required. Signing (every request): * Headers: `X-API-KEY`, `X-TIMESTAMP` (Unix seconds, within 300 s of server time; generate per request) and `X-SIGNATURE`. * `X-SIGNATURE` = Base64(HMAC-SHA256(key = API secret, message = apiKey + "|" + timestamp + "|" + canonicalBody)). Base64 of the raw digest, not hex. * canonicalBody: the JSON body with keys sorted at every nesting level, no whitespace (separators `,` and `:`), and every non-ASCII character escaped as lowercase `\uXXXX` (Python `json.dumps(body, sort_keys=True, separators=(",", ":"))`). Requests with no body (GET, DELETE) sign `{}`. Query parameters are not signed. * Send the exact canonicalBody string you signed as the request body, with `Content-Type: application/json`. * Test vector: key `3f1b2c4d-5e6f-4a7b-8c9d-0e1f2a3b4c5d`, secret `test-secret-do-not-use`, timestamp `1735689600`. Signing `{}` gives `6sCtVSRQjU9+2/af8gdwUAvY1l6Ii6ENcbRfanPkhY0=`. Body `{"customer_id":"78c99d71-f28f-47a9-8302-93b286efbe0e","amount":100.5,"currency":"INR","meta":{"note":"Café","b":2,"a":1}}` gives `l+DvQrzlKbsOSxSYOdWoWHEehcFRZfDJPKlLDkm2cSI=`. Deliver: 1. A typed `fetchPayinRate` function in this codebase's language and HTTP client. Reuse an existing Zapyd client and signer, or write one small shared client. 2. Config from `ZAPYD_API_KEY`, `ZAPYD_API_SECRET` and `ZAPYD_BASE_URL`. The secret stays on the server, never in a browser or app. 3. Return `data`. When `status` is false, throw an error with the HTTP status, `err_code`, `message` and `errors`. Don't show raw errors to end users. 4. Retry only 429 and 5xx: exponential backoff from 1 s, capped at 30 s, at most 5 attempts. 5. Amounts as strings. Types for every field above. 6. Tests: the signer against the test vector, and this call against sandbox. Reference: `https://docs.zapyd.com/api-reference-exchange/endpoint/payin/config/fetch-rate.md` | API Status Code | Response | Reason | | - | - | - | | 500 | Internal Server Error. | Internal Server Error | ## OpenAPI ````yaml GET /payin/fetch-rate openapi: 3.1.0 info: title: Zapyd API description: API for Zapyd - Customer, Payout, and Webhook services license: name: MIT version: 1.0.0 servers: - url: https://sandbox.zapyd.com/pos/api/v1 description: Payout API Base URL variables: base_url: default: https://sandbox.zapyd.com - url: https://sandbox.zapyd.com/cms/api/v1 description: Customer API Base URL variables: base_url: default: https://sandbox.zapyd.com security: - ApiKeyAuth: [] TimestampAuth: [] SignatureAuth: [] tags: - name: Customer description: Customer related operations x-displayName: Customer x-traitTag: true - name: Payout description: Payout related operations - name: Webhooks description: Webhook related operations - name: Widget description: Hosted buy/sell widget session initialization paths: /payin/fetch-rate: get: tags: - Payin description: >- Returns the current payin rate. All inputs are query parameters. For USD, `payment_method` and `sending_amount` are also required. parameters: - name: asset in: query required: true description: Crypto asset code, e.g. USDT or USDC schema: type: string example: USDT - name: fiat in: query required: true description: Fiat currency code, e.g. INR schema: type: string example: INR - name: network in: query required: true description: >- Blockchain network, for example tron or polygon. See supported_networks in Fetch Configuration. schema: type: string example: tron - name: payment_method in: query required: false description: Payin payment method. Required for USD. schema: type: string example: ach_pull - name: sending_amount in: query required: false description: >- Fiat amount the customer will pay. Required for USD, where it is checked against per-transaction limits. schema: type: string example: '100' responses: '200': description: Successful response content: application/json: schema: type: object properties: status: type: boolean example: true message: type: string example: Success data: type: object properties: asset: type: string example: USDT fiat: type: string example: INR rate: type: number format: decimal example: 87.2 network: type: string description: Network, uppercase. example: TRON fees: type: object description: >- Banking fee disclosure per payment method. Informational only; it is not applied to `rate`. additionalProperties: type: object properties: type: type: string description: Fee type example: banking_fee value: type: number example: 0.9 unit: type: string description: '`flat` or `percentage`' example: flat enum: - flat - percentage example: wire: type: banking_fee value: 0.9 unit: flat '400': description: Bad Request content: application/json: schema: type: object properties: status: type: boolean example: false message: type: string example: Bad Request data: type: 'null' err_code: type: string example: REQ_FIELD_MISSING errors: type: object additionalProperties: type: array items: type: string example: asset: - This field is required. amount: - This field is required. '500': description: Internal Server Error content: application/json: schema: type: object properties: status: type: boolean example: false message: type: string example: Internal Server Error data: type: 'null' err_code: type: string example: SYS_INTERNAL_ERROR errors: type: string example: Unexpected error occurred. Please try again later. servers: - url: https://sandbox.zapyd.com/pis/api/v1 description: Payin API Base URL components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-KEY description: API Key for authentication TimestampAuth: type: apiKey in: header name: X-TIMESTAMP description: Current timestamp in seconds since epoch SignatureAuth: type: apiKey in: header name: X-SIGNATURE description: HMAC SHA256 signature of the request encoded in Base64 ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.