Due to the large number of possible misspellings, not all of them can be accurately detected and corrected.
Washington DC 20020 Delivery Point Validation (DPV) provides the highest level of address accuracy checking.
[6] The USPS does not offer DPV validation on their website however there are companies that offer services to perform DPV verification and are certified by the USPS see also CASS Certification.
The USPS also licenses their services to third-party companies that provide the CASS certification in bulk.
[10][11] These third-party providers typically allow processing of address lists in CSV or Excel format.
They may also provide an API allowing the use of address verification services from within a program or website.
In the UK, the Royal Mail[12] provides address verification directly on their site and also licence their data to third-party providers to allow address checking services to be provided to organizations wishing to capture accurate addresses in their ecommerce checkout and online forms.Unlike the US system, the PAF is not geospatially hierarchic, it specifies the hierarchy of post sorting offices.
The PAF does not mandate a ‘street’ but can include a subordinate sorting office name; these typically occur in rural areas.