We help you optimize your mailings. One of the benefits of using Mailjoy is that we'll check your contacts' address with USPS for potential deliverability. Once you import or manually add contacts, you'll see a colored dot next to their address. Green dots mean that USPS has validated the address, while yellow dots mean that information may be missing (I.e an apartment number) or that USPS potentially doesn't recognize the address. This doesn't mean that it won't be successfully delivered, but instead, that there is more uncertainty around the address.