I am shopping around for an address standardization and validation DLL that I can integrate into my company's existing proprietary system will work with both C# and FoxPro using Windows servers and clients, that is CASS certified and does delivery point validation (DPV). It will validate new addresses as they are entered and scrub the existing historical address data.

I want a DLL that will work with .NET out of the box without having to fuss with interop issues. I'd like a good API with code examples, which could be in C++, Java, C#, VB, or FoxPro. I don't need marketing, census, or GPS data.

The packages that I am considering right now are:

AccuMail Gold Connections by Datatech SmartSoft Inc.
Address Cleanser & Coder by Group 1 Software
AddressObject by MelissaDATA
AddressVerifier by Anchor Computer Inc.
i/Lytics GLOBAL by Innovative Systems Inc.
MailRoom Toolkit by Satori Software
MailSTAR by AES Systems
Postalsoft by Firstlogic Inc.
Quality Stage by Ascential Software Corp
Quick Address by QAS
ZP4 by Semaphore Corp.

The price range is drastic. I have talked to sales at half of the companies and the licenses range from $600 to $85,000 a year. Since they are all CASS certified (meaning that they standardize addresses accurately enough for US Postal Service approval) and provide address existence validation (DPV), I don't understand the drastic price range.

Value, reliability, and scalability are also important. I expect that we might require up to 200 address real-time validations a minute, but probably much less.

If anyone has any feedback about these products, has had good or bad experience coding to them, has used their tech support for development issues, been responsible for handling the monthly data imports for them, or has any other suggestions or advice, I would appreciate it.

Thanks.