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Real Time Shipping Rates
More than one carrier can be used at the same time, to give your customers a wider array of shipping choices.
You should receive an email from USPS with your username and password for the API. These credentials should be valid for the USPS production and test servers.
USPS has a maximum shipping weight of 70 lbs. Store administrators should make sure that their RTShipping.USPS.MaxWeight Setting is set to 70 or less.
FedEx's API does not accept product dimensions with decimal places (ie 3.5). Remember that when entering dimensions for your products, they will be rounded up to whole numbers if you're using FedEx Real Time Shipping rates.
* To obtain your FedEx Web Services Meter Number, follow this procedure: