depends where you are
I am aware of a postal address checker based on the postcode & house name, but depends on your location.
In prcatise you ask the user for a house number (or name) and post code, the API then returns the rest of the address.
I guess there must be equivalents for the ZIP code in the US.
The only wrinkle with the UK system is that a Postcode ties the address down to anywhere between 1 & 10 physical addresses (ie there may be aorund 10 residential or low volume business addressess mapped to one postcode, you can have multiple postcodes mapped to one address where a single organsiation may have a vast post and they want it separated prior to delivery.