# Reference

- [Authentication](https://docs.2checkout.com/api-reference/reference/authentication.md)
- [JSON encoded requests](https://docs.2checkout.com/api-reference/reference/authentication/json-encoded-requests.md)
- [Product](https://docs.2checkout.com/api-reference/reference/product.md)
- [Product SKU](https://docs.2checkout.com/api-reference/reference/product-sku.md)
- [Product group](https://docs.2checkout.com/api-reference/reference/product-group.md)
- [Price options group](https://docs.2checkout.com/api-reference/reference/price-options-group.md)
- [Pricing configuration](https://docs.2checkout.com/api-reference/reference/pricing-configuration.md)
- [Shipping fees](https://docs.2checkout.com/api-reference/reference/shipping-fees.md)
- [Subscription](https://docs.2checkout.com/api-reference/reference/subscription.md)
- [Subscription history](https://docs.2checkout.com/api-reference/reference/subscription-history.md)
- [Single Sign On](https://docs.2checkout.com/api-reference/reference/single-sign-on.md)
- [Subscription usage billing](https://docs.2checkout.com/api-reference/reference/subscription-usage-billing.md)
- [Promotions](https://docs.2checkout.com/api-reference/reference/promotions.md)
- [Tax categories](https://docs.2checkout.com/api-reference/reference/tax-categories.md)
- [Cross Sell](https://docs.2checkout.com/api-reference/reference/cross-sell.md)
- [Upsell](https://docs.2checkout.com/api-reference/reference/upsell.md)
- [Customers](https://docs.2checkout.com/api-reference/reference/customers.md)
- [Order](https://docs.2checkout.com/api-reference/reference/order.md)
- [Place order](https://docs.2checkout.com/api-reference/reference/place-order.md)
- [Cart settings](https://docs.2checkout.com/api-reference/reference/cart-settings.md)
- [Payment methods](https://docs.2checkout.com/api-reference/reference/payment-methods.md)
- [Refunds](https://docs.2checkout.com/api-reference/reference/refunds.md)
- [Invoices](https://docs.2checkout.com/api-reference/reference/invoices.md)
- [Proposal](https://docs.2checkout.com/api-reference/reference/proposal.md)
- [Proposal history](https://docs.2checkout.com/api-reference/reference/proposal-history.md)
- [ChangeDeal](https://docs.2checkout.com/api-reference/reference/changedeal.md)
- [CancelDeal](https://docs.2checkout.com/api-reference/reference/canceldeal.md)
- [Additional fields](https://docs.2checkout.com/api-reference/reference/additional-fields.md)
- [Partners](https://docs.2checkout.com/api-reference/reference/partners.md)
- [Resellers](https://docs.2checkout.com/api-reference/reference/resellers.md)
- [Channel Manager settings](https://docs.2checkout.com/api-reference/reference/channel-manager-settings.md)
- [Partner subscriptions](https://docs.2checkout.com/api-reference/reference/partner-subscriptions.md)
- [Affiliates](https://docs.2checkout.com/api-reference/reference/affiliates.md)
- [Accounting](https://docs.2checkout.com/api-reference/reference/accounting.md)
- [Leads](https://docs.2checkout.com/api-reference/reference/leads.md)
- [Churn prevention campaigns](https://docs.2checkout.com/api-reference/reference/churn-prevention-campaigns.md)
- [Models](https://docs.2checkout.com/api-reference/reference/models.md)


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# Agent Instructions: Querying This Documentation

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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.2checkout.com/api-reference/reference.md?ask=<question>
```

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.