# 13. Payment Inquiry Paywall offers multiple alternative services for payment inquiry operations. The results provided by these services are very similar. You can quickly complete your integration by choosing the service that best fits your needs or technical infrastructure. **Services;** * **`MerchantUniqueCode`** Query payment by 🔗 * **`UniqueCode`**Query payment by 🔗 * **`ProductId`** Query payment by 🔗 * **`TrackingCode`** Query payment by 🔗 --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://developer.paywall.one/payment-orchestration-integration-document/payment-service/13.-payment-inquiry.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.