Select the optimal shipping option based on cost, speed, and reliability tradeoffs

Steps

1. After building a cart and providing a validated destination address, call the merchant's shipping options endpoint or read the options returned during cart/checkout flow; capture carrier, service level, estimated delivery date, and cost for each option.
2. Apply user-defined preferences as a scoring function: e.g., weight delivery speed vs cost according to a configurable urgency parameter (high urgency = minimize transit days, low urgency = minimize cost).
3. Filter out shipping options that do not meet hard constraints: minimum required delivery date, prohibited carriers, or options that don't include tracking.
4. If the cheapest option is within a configurable threshold of the fastest option (e.g., cost difference < $2), prefer the faster option to reduce delivery risk.
5. Log the selected option and the full set of alternatives with scores so the selection rationale is auditable.
6. If no shipping option meets constraints (e.g., merchant cannot deliver to the address within the required timeframe), emit a fallback event to try an alternative merchant.