When to choose Enterprise Application Integration Middleware?

Question

I work in a software company that delivers a software product. Many times we must integrate with other applications. 70% of the time we integrate with a single application. Currently we do not use middleware (MuleESB, Biztalk, ...) in these situations: the data conversion, transport conversion, etc is handled inside the applications.

Wouldn't it be better to ALWAYS use a middleware solution? (no matter if your integrating with 1 or more systems) This way, all the customizations (data formatting, restructuring, transport conversions) of both parties, can be handled by the middleware, instead of by the applications.

Logically this seems to me the right approach. But I ask myself: Is middleware in the case of two applications justifiable?

Answer 1

I found this to be a useful read when considering appropriate architecture. If you get a chance to see Richard Seroter's "Decision Framework" presentation, you should.

Answer 2

In practical terms, you will always be using a "Middleware" solution, either custom or packaged.

I'd look at it this way, rather than requireing a "middleware" package, I'd focus on making the app itself integration friendly by using a consistent and as-standard-as-practical API for exchanging data.

Then the decision on what "middleware" to use is more driven by the circumstance on site. If the customer has only one app to integrate, then a simple custom solution might be perfectly serviceable. If they have 5 apps and defined processes for each, then a package makes more sense.

I don't always use middleware, but when I do, I use BizTalk. ;)

Answer 3

Wiki site on Publish subscribe pattern http://en.wikipedia.org/wiki/Publish/subscribe shows an interesting comparison between how publish subscribe relates to client server.