Comment by ComputerGuru
9 months ago
The United States Postal Service probably has the best in the world, though its training probably restricts it to a subset of possible inputs. I wonder if it would be possible to get a senator or congressman to push for open sourcing it.
I believe the USPS system makes extensive use of knowledge of possible valid addresses so you're probably right that it wouldn't be generally applicable. Their _dataset_ must be glorious (and extremely confidential) though.