In line with the long term vision of the ISBNdb.com project the access to the data from individuals should be free of charge. In reality, this is extended to even broader range of application -- as long as the application does not send an excessive amount of requests and meets our pretty liberal terms and conditions -- most uses are OK, individual, research or commercial.

But having said that, the server has to control the number of requests sent in and block excessive requests.

As mentioned in the previous section, one thing practically all requests share is a requirement to identify an account the request relates to. Based on this information the server can decide to grant or decline the request.

Identification is done by setting a request variable called 'access_key' to a value of a key. Each key uniquely identifies an account it was generated for, but each account can have multiple keys and assign different limits to them to facilitate development, testing and production use of applications.

To generate keys you need to create an account with ISBNdb.com and then go to access keys manager.

Here is an example of passing a key to retrieve book's data: