You can integrate Adyen's client-side libraries with different server-side flows. Sessions flow is the default integration that we recommend and that meets the requirements for most online payments integrations.
Choose your server-side implementation
Before you integrate with a client-side library, choose the server-side flow depending on the technical details and depending on the use cases that you want your integration to support.
Sessions flow: a single API request
Your server makes a single Checkout API request to the  /sessions endpoint. Adyen sends payment data from our server to your client-side application. You can optionally implement additional client-side methods to support some additional use cases.
Advanced flow: three API requests
Your server makes three Checkout API requests:  /paymentMethods,  /payments, and  /payments/details. Adyen sends payment data from our server to your server. This flow supports more use cases.
Sessions flow with additional methods
The client-side libraries include additional methods that to make requests from your server to the  /payments and  /payments/details endpoints, so that you get responses on your server.
  
Supported use cases
| Description | Sessions flow | Sessions flow with additional methods | Advanced flow | 
|---|---|---|---|
| Make a payment with any available payment method. |  |  |  | 
| Make a partial payment with a gift card and the rest with another payment method. |  |  |  | 
| Confirm an additional action on your server. |  |  |  | 
| Confirm a redirect on your server. |  |  |  | 
| Implement checks on your server, like inventory checks, before making a payment. |  |  |  | 
| Update the payment amount before making a payment, for example, when the shopper updates their shopping cart. |  |  | |
| Implement Apple Pay and Google Pay express checkout. |  | ||
| Change the order of payment methods for an individual transaction. |  | ||
| Insert a separate page for the shopper to agree to terms and conditions before making a payment. |  | 
Integration comparison
| Integration features | Sessions flow | Sessions flow with additional methods | Advanced flow | 
|---|---|---|---|
| Integration effort | Light | Medium | Medium | 
| Number of endpoint requests from your server | 1 | 2 or 3 | 3 | 
| Handling redirects | Client-side | Client-side and server-side | Client-side and server-side | 
| Handling additional actions | Client-side | Client-side and server-side | Client-side and server-side | 
Get started
Choose the server-side implementation that meets your needs to learn how to integrate with Adyen. We offer solutions for web, mobile devices, and cross-platform.