I tried faircab app and it has a nice feature, where you can enter start and stop address. You can just enter e.g. "empire state" and when you press a button, it will suggest you "empire state building" and it's complete address (or even more suggestions).
I need this service for Europe. How is this done, using some Google API?
There are a number of libraries commercially available that do "Address normalization". They download the US postal service address database. It allows them to standardize the address and validate that the street really exists.
You can take a look at the Google's geocoding apis. These enable you to enter address, part of address or co-ordinates and return places around or similar places that you can use as suggestions.
Dixie, I work for a company called SmartyStreets -- we're in the address validation industry. Jay is right: there are many services which will do what you require, but only a few are accurate and certified by government institutions.
I realize you need this service for Europe, and even though I don't know the workings of the post authorities for those countries, the principles are the same: license restrictions apply (see my comment above) to free services, and you'll need to find one that is approved for use for automated queries.
Also, beware of address approximation vs. address verification. The former doesn't guarantee the address exists (this is like Google or Bing). The latter is guaranteed to exist because it's being processed against an official government-provided database and the software is certified to be accurate. For a model of this type of company/service, try looking at SmartyStreets to see what you need for Europe. In our case, we're CASS-Certified by the USPS, the government agency that regulates mail. You want the equivalent for Europe.
Update: SmartyStreets now does international address verification.
