# Billie Docs Documentation > Documentation for Billie Docs Append .md to any documentation page URL to get its markdown version. ## Guides - [Introduction](https://docs.billie.io/docs/introduction.md) - [Integration Types](https://docs.billie.io/docs/billie-direct-vs-klarna-integration.md) - [Overview](https://docs.billie.io/docs/payment-flow-overview.md) - [Order Creation](https://docs.billie.io/docs/introduction-1.md) - [Changing the order amount](https://docs.billie.io/docs/changing-the-order-amount.md): There can be many reasons why an order amount needs to be changed after the initial order creation. Currently, the amount of all orders via Billie can only be lowered (not raised). - [Cancelation of an order](https://docs.billie.io/docs/raising-the-order-amount.md) - [Get Started via API](https://docs.billie.io/docs/get-started-with-billies-api-integration.md) - [Get Started via Partner](https://docs.billie.io/docs/get-started-with-billies-integration-via-klarna.md) - [Testing](https://docs.billie.io/docs/sandbox-testing-platform.md) - [International test buyer accounts](https://docs.billie.io/docs/international-test-buyer-accounts.md) - [Partner Checkout Design Guide](https://docs.billie.io/docs/checkout-design-guide-psp.md) - [Go-Live Checklist](https://docs.billie.io/docs/go-live-checklist.md) - [Material for global markets](https://docs.billie.io/docs/material-for-global-markets.md) - [Invoice Content](https://docs.billie.io/docs/invoice-description-partner.md) - [Material for Sweden (via Klarna)](https://docs.billie.io/docs/go-live-in-sweden.md) - [Model Clauses for T&Cs](https://docs.billie.io/docs/terms-model-clauses.md) - [Invoice Content](https://docs.billie.io/docs/invoice-description-se.md) - [Direct Checkout Design Guide](https://docs.billie.io/docs/billie-payment-brand-guide.md) - [Go-Live Checklist](https://docs.billie.io/docs/go-live-checklist-direct.md) - [Material for Germany](https://docs.billie.io/docs/germany.md) - [Model Clauses for T&Cs](https://docs.billie.io/docs/sample-text-agb.md) - [Billie Shipping Policy (delivery and return)](https://docs.billie.io/docs/billing-shipping-policy.md) - [Invoice Description](https://docs.billie.io/docs/invoice-description.md) - [Intro](https://docs.billie.io/docs/conversion-optimisation.md) - [Checkout](https://docs.billie.io/docs/checkout.md) - [Product Detail Page](https://docs.billie.io/docs/product-detail-page.md) - [Product List Page](https://docs.billie.io/docs/product-list-page.md) - [Sitewide](https://docs.billie.io/docs/sitewide.md) - [Micro Page / FAQs](https://docs.billie.io/docs/micro-page-faqs.md) - [Newsletter](https://docs.billie.io/docs/email.md) - [Abandoned Cart Notification](https://docs.billie.io/docs/abandoned-cart.md) - [Social & Paid Media](https://docs.billie.io/docs/social-media-de.md) - [FAQ Content](https://docs.billie.io/docs/faq-content.md) - [Templates](https://docs.billie.io/docs/templates.md) - [Billie Marketing Badge](https://docs.billie.io/docs/logos-trademarks.md) - [Banners](https://docs.billie.io/docs/banners.md) ## Integration Docs - [Integration Checklist](https://docs.billie.io/reference/integration-checklist.md) - [Authentication](https://docs.billie.io/reference/authentication.md) - [Request OAuth Token](https://docs.billie.io/reference/oauth_token_create.md): ### Flow The client sends a POST request with following body parameters to the authorization server: * `grant_type` with… - [Validate OAuth Token](https://docs.billie.io/reference/oauth_token_validate.md): Validates the `Authorization: Bearer XXXX` OAuth 2.0 token header and returns a successful response with `client_id` and `user_id` or fails if it's invalid. - [Revoke OAuth Token](https://docs.billie.io/reference/oauth_token_revoke.md): Revokes the oAuth token using the token from the `Authorization: Bearer XXXX` header and returns a 204 response - [Checkout Session Confirm](https://docs.billie.io/reference/confirm_authorization_v2.md): **Purpose** Confirms the creation of an authorization where the buyer gave consent to the purchase and was accepted by Billie. **Preconditions:** - Session `id` of the Session Create Call -… - [Checkout Client](https://docs.billie.io/reference/checkout-widget.md) - [Checkout Session Create](https://docs.billie.io/reference/create_checkout_session_v2.md): **Purpose:** Creates a session ID that is used to initiate the widget for a dedicated checkout session with a customer. **Preconditions:** - n/a **Success:** - Response Code: HTTP 200 -… - [Hpp Checkout Session Create](https://docs.billie.io/reference/create_hpp_checkout_session_v2.md): **Purpose** Creates a session ID and redirect URL that are used to initiate a Hosted Payment Page. **Preconditions:** - All the authorization related data is present. - Accept and decline URL are… - [Get Authorization](https://docs.billie.io/reference/get_checkout_session_authorization_v2.md): Return last authorization for the given checkout session. - [Create Order](https://docs.billie.io/reference/order_create_v2.md): **Purpose:** Creates an order directly from the backend without buyer interaction. **Preconditions:** - All the order related data is present **Success:** - Response Code: `HTTP 200` -… - [Get Legal Forms](https://docs.billie.io/reference/get_legal_forms.md): **Purpose:** Retrieves a list of valid legal form codes in relation to the legal for names. **Success:** - Response Code: `HTTP 200` - [Order States & Decline Reasons](https://docs.billie.io/reference/order-states-and-decline-reasons.md) - [Cancel Order](https://docs.billie.io/reference/order_cancel_v2.md): **Purpose:** Cancels an entire order. For cancellations after capture, please see Refunds. **Preconditions:** - `id`: The unique identifier of the order **Success:** - Response Code: `HTTP 204` - [Get Order Details](https://docs.billie.io/reference/order_get_details_v2.md): **Purpose:** Retrieves full information about an order. **Preconditions:** - `id`: The unique identifier of the order **Success:** - Response Code: `HTTP 200` - [Update Order](https://docs.billie.io/reference/order_update_v2.md): **Purpose:** Updates order information before capture. - Adding an external code that represents the order ID of the merchant if not already submitted previously. - Changes the order amount… - [Get Invoice](https://docs.billie.io/reference/get_invoice.md): **Purpose:** Retrieves full information about a capture. **Preconditions:** - `captureId`: The unique identifier of the capture **Success:** - Response Code: `HTTP 200` - [Confirm Invoice Payment](https://docs.billie.io/reference/invoice_payment_confirm.md): **Purpose:** Confirms that the buyer (your customer) paid a given amount relating to a capture to your bank account, rather than Billie's. Billie will reduce the outstanding amount accordingly and… - [Create Invoice](https://docs.billie.io/reference/invoice_create.md): **Purpose:** Captures against an order. This can be done against part of the authorised order amount (partial capture) or its entire amount (full capture). For partial captures, please submit each… - [Update Invoice](https://docs.billie.io/reference/invoice_update.md): **Purpose:** Provides the external code relating to a capture (the invoice number in your backend) and URL to your invoice document (allowing Billie to obtain it) if not already provided under… - [Invoice States](https://docs.billie.io/reference/invoice-state-desc.md) - [Cancel Invoice](https://docs.billie.io/reference/invoice_cancel_v2.md): **Purpose:** Refunds the full amount of a past capture. **Preconditions:** - `captureId`: The unique identifier of the capture **Success:** - Response Code: `HTTP 204` - [Create Credit Note](https://docs.billie.io/reference/create_credit_note.md): **Purpose:** To refund against a previous capture. This can be done against part of the captured amount (partial refund) or its entire amount (full refund). **Preconditions:** - `captureId`: The… - [Webhooks](https://docs.billie.io/reference/webhooks.md) - [Overview](https://docs.billie.io/reference/overview-1.md) - [Shopware Integration](https://docs.billie.io/reference/shopware.md) - [JTL Integration](https://docs.billie.io/reference/jtl-integration.md) - [WooCommerce Integration](https://docs.billie.io/reference/woocommerce.md) - [SDK Integration](https://docs.billie.io/reference/sdk-integration.md) - [Klarna](https://docs.billie.io/reference/klarna.md) - [Klarna Payments via API](https://docs.billie.io/reference/integration-via-klarna-payments.md) - [Klarna Payments via Computop](https://docs.billie.io/reference/klarna-payments-integration-computop.md) - [Kustom Checkout Integration](https://docs.billie.io/reference/klarna-checkout-integration.md) - [Mollie](https://docs.billie.io/reference/mollie.md) - [Adyen](https://docs.billie.io/reference/adyen.md) - [Stripe](https://docs.billie.io/reference/stripe.md) ## Pages - [404](https://docs.billie.io/page/error-page.md)