UPS shipping rates can be integrated into an online shopping cart by following these steps:

Obtain an API key: To access the UPS shipping rates, you will need to obtain an API key from UPS. You can do this by signing up for a UPS Developer account and requesting an API key.

Integrate the API into your shopping cart: Once you have an API key, you can integrate the UPS shipping rates into your shopping cart by making API calls to the UPS server, passing in your API key and the relevant shipping information, such as the origin and destination addresses, weight and dimensions of the package, etc.

Parse the response: The UPS API will return a response containing the shipping rates for the specified shipment. You can then parse the response to extract the relevant shipping rates and display them to the customer in your shopping cart.

Update the checkout process: After the shipping rates are displayed to the customer, you can update your checkout process to allow the customer to choose their preferred shipping method and calculate the total cost of the purchase, including the shipping cost.

By integrating the UPS shipping rates into your online shopping cart, you can provide your customers with accurate and up-to-date shipping information, helping to ensure a seamless and user-friendly checkout experience.