Checkout optimisation improves the final stage of the ordering process, from basket to confirmation page, in order to reduce abandoned purchases and make completing an order as simple as possible. It covers guest checkout, few form fields, understandable error messages and a transparent view of total cost and delivery time. Design freedom stops where section 8 FAGG, the Austrian distance selling act, sets binding rules: immediately before the customer places an order, the essential characteristics of the goods or service, the total price, recurring costs, the cost of using the means of distance communication, the contract term and cancellation conditions as well as any minimum duration must be stated clearly and prominently, and the order button must be labelled legibly and exclusively with the wording "zahlungspflichtig bestellen" or an equally unambiguous phrase – additions on the button itself are not covered by that.
In practice
It often turns out that a multi-step checkout with a progress indicator works better than a single overloaded form, because customers can judge how much is left to do. Mobile optimisation is now a given, since a substantial share of orders comes from smartphones, which makes large touch targets, autofill support and mobile payment methods such as Apple Pay or Google Pay important. Technically, the checkout should also be optimised for Core Web Vitals, because long load times at this sensitive point in the process lead to abandonment. Review the mandatory elements separately before any redesign: in Austrian distance selling, cost transparency is not just a UX recommendation but a requirement under section 8(1) FAGG, and breaching the button labelling rule means, under section 8(2) FAGG, that consumers are not bound by the contract at all. Whether delivery restrictions apply, and which means of payment are accepted, must also be stated clearly no later than at the start of the ordering process.