> For the complete documentation index, see [llms.txt](https://developer.paywall.one/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.paywall.one/payment-orchestration-integration-document/payment-service/13.-payment-inquiry.md).

# 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 🔗