What are the pros and cons of using an api for your web app.

php mysql codeigniter rest xml-rpc

PROs:

You wont have to change the second app if you make changes in calls to the db.
You could possibly serve more requests by replicating the front end, also taking different types of incoming requests
You can reuse the data access app in other places

CONs: might be overkill depending on your needs

php mysql codeigniter rest xml-rpc

Pros

It would make your application more modular allowing for changes to be made down the road with out breaking other parts of the application
It would make testing easier as you could test the two parts Independently of each other

Cons

Could be overly complex leading to maintenance problems
There is always overhead introduced due to abstraction so slower proformence would result