> ## Documentation Index > Fetch the complete documentation index at: https://docs.stablepayfi.ai/llms.txt > Use this file to discover all available pages before exploring further. # Retrieve payment details > Retrieve payment details by the `payment_id` returned from a subscription invoice. This `payment_id` identifies the payment generated for a subscription charge and can be used to confirm payment status, amount, and on-chain payment information. ## OpenAPI ````yaml /en/api/subscription-openapi.json get /api/v1/payment/{payment_id} openapi: 3.1.0 info: title: StablePay Subscription API version: '2026-04-20' summary: >- StablePay subscription endpoints: subscriptions, payment sessions, payment methods, refunds, and webhook events. description: >- OpenAPI specification for the StablePay subscription service. ## Basics - Base URL: `https://api.stablepay.co` - Prefix: `/api/v1` - Protocol: HTTPS - Format: JSON (UTF-8) ## Authentication All endpoints require `Authorization: Bearer {api_key}`. Write operations should also include replay-protection headers: `X-StablePay-Timestamp`, `X-StablePay-Nonce`, `X-StablePay-Signature`. ## Amount precision Amount fields are expressed in the smallest unit of the currency (e.g. `1999` represents $19.99 for USD; USDT/USDC use 6 decimal places). servers: - url: https://api.stablepay.co description: Production security: - bearerAuth: [] stablepayTimestamp: [] stablepayNonce: [] stablepaySignature: [] tags: - name: Subscriptions description: Create, retrieve, list, and cancel subscriptions. paths: /api/v1/payment/{payment_id}: get: tags: - Subscriptions summary: Retrieve payment details description: >- Retrieve payment details by the `payment_id` returned from a subscription invoice. This `payment_id` identifies the payment generated for a subscription charge and can be used to confirm payment status, amount, and on-chain payment information. operationId: getSubscriptionPaymentDetail parameters: - $ref: '#/components/parameters/PaymentId' - $ref: '#/components/parameters/XStablePayTimestamp' - $ref: '#/components/parameters/XStablePayNonce' - $ref: '#/components/parameters/XStablePaySignature' responses: '200': description: Retrieved successfully. content: application/json: schema: $ref: '#/components/schemas/PaymentSession' '400': description: Invalid request parameters. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Authentication failed. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Payment session not found or not accessible. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' components: parameters: PaymentId: name: payment_id in: path required: true description: >- Payment ID returned by a subscription invoice, used to retrieve subscription charge payment details. schema: type: string XStablePayTimestamp: name: X-StablePay-Timestamp in: header required: true description: Unix timestamp in seconds. Must be within 5 minutes of server time. schema: type: string example: '1735689600' XStablePayNonce: name: X-StablePay-Nonce in: header required: true description: Replay-protection nonce, 16-64 characters. Use a fresh UUID per request. schema: type: string minLength: 16 maxLength: 64 example: 550e8400-e29b-41d4-a716-446655440000 XStablePaySignature: name: X-StablePay-Signature in: header required: true description: >- Lowercase hex HMAC-SHA256 of `{timestamp}.{nonce}.{requestBody}` signed with the merchant API Secret. For GET requests, `requestBody` is an empty string. schema: type: string example: a1b2c3d4e5f6... schemas: PaymentSession: type: object required: - id - amount_total - currency - payment_status - created - expires_at properties: id: type: string description: Payment session ID. amount_total: type: integer format: int64 description: Total amount in minor units. currency: type: string description: Merchant ledger currency, returned in lowercase. payment_status: $ref: '#/components/schemas/PaymentStatus' created: type: integer format: int64 description: Creation time, Unix seconds. expires_at: type: integer format: int64 description: Expiration time, Unix seconds. url: type: string format: uri description: Checkout URL. line_items: type: array items: $ref: '#/components/schemas/LineItem' description: Line items. tax_amount: type: integer format: int64 description: Tax amount in minor units. shipping_amount: type: integer format: int64 description: Shipping amount in minor units. exchange_rate: type: string description: Exchange rate when currency conversion applies. target_currency: type: string description: Actual on-chain payment currency, for example `USDT`. target_amount_total: type: integer format: int64 description: Target amount in target-currency minor units. rate_locked_at: type: integer format: int64 description: Rate lock time, Unix seconds. subscription_id: type: string description: Related subscription ID, returned for subscription payments. invoice_id: type: string description: Related invoice ID, returned for invoice or subscription payments. metadata: type: object additionalProperties: type: string description: Merchant metadata. ErrorResponse: type: object description: Error response. properties: error: type: object properties: type: type: string description: Error type. code: type: string description: Error code. message: type: string description: Error message. param: type: string description: Related parameter. doc_url: type: string description: Error documentation URL. decline_code: type: string description: Decline code. request_log_url: type: string description: Request log URL. charge: type: string description: Related payment ID. request_id: type: string description: Request ID. timestamp: type: integer format: int64 description: Error timestamp in Unix seconds. PaymentStatus: type: string enum: - pending - processing - paid - failed - expired - canceled description: >- Payment status. `confirming` is returned as `processing`; `completed` is returned as `paid`. LineItem: type: object required: - price_data - quantity additionalProperties: false properties: price_data: $ref: '#/components/schemas/PriceData' quantity: type: integer minimum: 1 description: Item quantity. Must be greater than 0. PriceData: type: object properties: id: type: string description: >- Price ID. This field is usually not returned by the current HTTP response. currency: type: string description: Currency. product: type: string description: Product ID or product name. unit_amount: type: integer format: int64 description: Unit amount in minor units. recurring: $ref: '#/components/schemas/RecurringConfig' RecurringConfig: type: object properties: interval: type: string enum: - day - week - month - year description: Billing interval. interval_count: type: integer description: Billing interval count. Currently fixed to 1 by the server. securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: API Key description: Bearer API Key, for example `Bearer sk_live_xxx`. stablepayTimestamp: type: apiKey in: header name: X-StablePay-Timestamp description: Unix timestamp in seconds. Must be within 5 minutes of server time. stablepayNonce: type: apiKey in: header name: X-StablePay-Nonce description: Replay-protection nonce, 16-64 characters. Use a fresh UUID per request. stablepaySignature: type: apiKey in: header name: X-StablePay-Signature description: >- Lowercase hex HMAC-SHA256 of `{timestamp}.{nonce}.{requestBody}` signed with the merchant API Secret. For GET requests, `requestBody` is an empty string. ````