Page Flow Approach

The checkout process is built on the Page Flow architecture.

1. Step-based Progression: Each step focuses on its own responsibility. The user completes only one task at a time (for example: selecting an address or choosing a payment method).

2. Conditional Navigation: Some steps may be automatically skipped depending on the user's state. For example, the email collection step is unnecessary for logged-in users.

3. Revisability: The user can return to previous steps at any time to update their information. The system automatically handles how this change affects subsequent steps.

4. State Preservation: Even if the user leaves the checkout process, they can resume from where they left off within a certain time period.