We strongly recommend before jumping into the recipes to have an adequate understanding of some of the core Affirm principles and products. All of our guides will provide the necessary resources and documentation, but having this fundamental knowledge will help significantly.
## API attributes
Some attributes from Affirm APIs completely change the dynamic or nature of some of Affirm's product(s).
[POST vs. GET Method](🔗): This will provide redirection action and response mechanism handling for different checkout events.
[Checkout Expiration Timer](🔗): This feature will enable restriction on the checkout expiration. A timer will be displayed at the top of the checkout session with a count down.
## Custom integration
Some integrations will require the use of additional resources to achieve the expected result for your business model.
[Multiple Financing Programs](🔗): Affirm offers select loan offers and programs to consumers based on product or cart attributes that are defined in your e-commerce or marketing platform.
[Device upgrades](🔗): This is very specific to the mobile space and their unique financing options. It enables the customer to pay and reach a precise loan balance on their existing phone. This threshold will let them be eligible for a trade-in or a phone upgrade.