{
"title": "Session walkthrough: checkout validation moved in front of order submission",
"summary": [
"This session moved checkout validation earlier in the flow so missing address and payment data now fail before the order request is built.",
"The main behavior change is that invalid carts stay on the page with focused inline errors, while valid carts still follow the same backend path as before."
],
"sections": [
{
"title": "How the request flow changed",
"text": [
"The checkout page now sends the submit intent through a validation gate before the order payload is assembled.",
"Only validated carts continue to the orders API, which keeps the backend contract stable while shifting obvious failures closer to the user."
],
"diagram": {
"type": "sequence",
"nodes": [
"User",
"Checkout Page",
"Validation Gate",
"Orders API"
],
"edges": [
{
"from": "User",
"to": "Checkout Page",
"label": "tap place order"
},
{
"from": "Checkout Page",
"to": "Validation Gate",
"label": "check cart"
},
{
"from": "Validation Gate",
"to": "Checkout Page",
"label": "inline errors"
},
{
"from": "Validation Gate",
"to": "Orders API",
"label": "valid payload"
}
]
}
},
{
"title": "What happens on valid and invalid input now",
"text": [
"Invalid submissions stop locally and point the user at the exact field that needs attention instead of waiting for a round-trip failure.",
"Valid submissions still proceed through the normal order creation path, so the behavior change is mostly about earlier feedback and cleaner rejection handling."
],
"diagram": {
"type": "flow",
"nodes": [
"Invalid cart data",
"Inline field errors",
"Valid cart data",
"Orders API"
],
"edges": [
{
"from": "Invalid cart data",
"to": "Inline field errors",
"label": "stop locally"
},
{
"from": "Valid cart data",
"to": "Orders API",
"label": "continue"
}
]
}
},
{
"title": "Which parts of the system now own the behavior",
"text": [
"The checkout page still owns the submit action, but the validators now gate what can reach the submit controller.",
"That separation makes the UI feedback path explicit without changing the downstream API responsibilities."
],
"diagram": {
"type": "component_graph",
"nodes": [
"Checkout Page",
"Address Validator",
"Payment Validator",
"Submit Controller",
"Orders API"
],
"edges": [
{
"from": "Checkout Page",
"to": "Address Validator",
"label": "address fields"
},
{
"from": "Checkout Page",
"to": "Payment Validator",
"label": "payment fields"
},
{
"from": "Address Validator",
"to": "Submit Controller",
"label": "validated cart"
},
{
"from": "Payment Validator",
"to": "Submit Controller",
"label": "validated cart"
},
{
"from": "Submit Controller",
"to": "Orders API",
"label": "create order"
}
]
}
}
],
"verification": {
"text": [
"The invalid-submission regression is covered by an automated checkout test that asserts field-level errors appear before any network request is sent.",
"A manual browser pass confirmed that valid carts still place orders successfully after the validation gate was introduced."
]
}
}