When I do go back to selling on eBay, I plan to remove GSP and instead offer direct shipping to the buyer using FedEx International Priority. I have a duties calculator provided by easyship.com that gives reasonably close duties estimates. I do not want to use USPS since I paid for their fastest service (Express Int'l) only to have the item sit in chicago for an entire month before it moved again to to buyer's... Source: over 3 years ago

There are online formatters like smartystreets.com which can validate and format your international address. Is this what you are looking for? Source: over 2 years ago

What I've noticed after watching those sneaker botting videos is that they can make as many emails, proxies and debit cars numbers as they want but.... Not addresses. According to this video they mix up the way their address are written which somehow fools their system into thinking there aren't repeats even though the shoes some how end up at the same address. What these sites really need is a third party service... Source: about 3 years ago

At one point they used SmartyStreets to validate your address and if it thinks your duplex and your neighbor is the same house, they'll be treated as one so you cannot get fiber now. Source: over 3 years ago

You can give smartystreets.com a try however for that many records it might cost you just a bit. Source: over 3 years ago

A good source that is free in small quantities for all states and in the world: smartystreets.com. Source: over 3 years ago