I'd love to use Lob: they have a clean API, good support, they can send letters and postcards anywhere in the world... but they're based in the US, and the problem is that mail might take a while to reach other parts of the world, for example Europe.

According to their website: for First Class mail, it's 4 to 6 business days _plus_ an additional 5 to 7 days, while for Standard Mail, anywhere from 7 to 21 business days (and USPS does not provide delivery time guarantees for Standard Mail).

What are my options, were I look to target the European market? A delivery time of 4-6 business days would be something I'd love to have.