Software as a Service (SaaS) is an interesting area to learn about. Fred Chong writes regularly about SaaS. In one of his posts, he has written about Practical Limits for Configurability for SaaS applications.

He defines 3 aspects that define configurability for a hosted solution.

1. Capability to modify behavior through Code Upload
2. Supply New business logic
3. Change business data model for the application

Interesting. So why do ASP’s want their application to be configurable.

1. Because they can provide a customized offering to their customers. SalesForce provides AppExchange and API’s that you can build to.
2. Reduce costs associated with maintenance and change

I am essentially interested in how can ASP’s make their and their customer’s lives easier by allowing them to supply new business logic.

We are talking business rules here. Any design that ASP’s use must account for business logic and rule externalization.

Why? Because, if these are buried in code or inside of databases as stored procs, out goes your flexibility and configurability.

So, what kind of rules are we talking about here.

1. Presentation rules to customize and configure user interfaces
2. Workflow configuration rules. For example, work allocation rules in the case of Accounts Receivable managers to intelligently assign workflow of accounts to large teams of collectors.
3. Data processing and validation rules, like in the case of an Health care Administration Services provider.

Of course, these are just some broad categories, and is by no means complete.

The biggest benefit that ASP’s gain by externalizing their business logic/rules is one of a reduction in maintenance cost. Changes to the business rules are easier to test and make as they are anyways externalized from the rest of the application. This also fits with the regular updates model followed by most ASP’s.

The other benefit is improved visibility for the business and may be for the customer if some of the rules are exposed to the customer.

The third is simpler auditabiity.

Capabilities like “Invoking historical rules” are available out of the box with business rules management systems that might be very difficult to implement otherwise.This might be important in the case of finserv ASP’s

Overall, I believe that business rules technology will be a good fit for hosted SaaS application that involve a host of business rules. And certainly better than using stored procs or business logic classes.