word-tax.c is a C command line* application that takes the ISO 3166* country code and registration number of a client company (and optionally its address), and determines what tax to charge it regardless of who is selling the product or service. Currently this application only supports and tests for the need to charge the European VAT tax.
According to European VAT rules, any European buyer should be charged VAT if:
The first point should be tested by your code, but how do you avoid problems with State audits if your buyers lie to you (by claiming to be from another European country with a fake registration number) in order not to pay VAT?
- it's registered in the same country as the seller, or
- is not registered for trade (e.g.: the buyer is a person and not a company).
It's in this process that this application comes in. It analyzes the buyer information you supply to it. If the country does not belong to the European Union, the application returns immediately stating no VAT to charge. Otherwise it queries the European VIES* database to learn if the supplied registration number is in fact a registered company. If true, it returns indicating "VAT exempt", otherwise it returns indicating "subject to VAT".
If you supply it with the buyer's address, world-tax will also find out if the buyer is within a region of a European Union country that is VAT exempt, such as some islands and enclaves according to European directives.
Though typically used in real time in a shopping cart or order form (and for this reason we can specify the amount of time we're willing to wait for an answer from the VIES database), this application was also prepared for batch verifications, making multiple parallel queries to the VIES database for enhanced speed.
Licensed according to one of the options on the left:
The application is written in ANSI C with POSIX.1 / WIN32 network extensions and should therefore run practically on any computer platform, including Windows and Unix/Linux.
The purchase of this software makes you the owner of a ZIP file that will be e-mailed to you, containing:
- The source-code or an executable binary, depending on the purchased licensing (see to the left).
You will also be eligible for free e-mail technical support and free upgrades, should you find any flaws that are fixed.
This application has been developed under Windows XP and Vista, compiled with GCC and was recompiled, installed and is in production in LAMP platforms* since 2003. world-tax is used by this site to determine the final amounts to pay during the ordering of a product/service.
The application is also pre-installed and accessible to hosting clients. It has no known bugs.
Even though this application doesn't need to run with special permissions, during its development special care was taken with the strict validation of buffers in order to prevent any buffer overflow attacks.