The cost effectiveness of open source business rule management systems (BRMS) are surely self evident – they are free aren’t they? Isn’t that always better than paying a traditional vendor through the nose? Isn’t this decision one of technology’s no brainers? Well no, I don’t think it is…

I’ve been frequently asked whether (and sometimes greeted with the assumption that) open source business management systems (OS BRMS) are much better value for money that vendor products. The assertion is they offer the same functionality for much less money. Surely if the produce is free and open source this is always a better option – yes?

Well, er, no actually. This is not always the case. Here are some arguments I’ve heard used for the open source BRMS products (you know the ones I’m talking about) and the flaws with them:

  1. Open Source BRMS Are Cheaper: actually this is not always the case. Although the initial outlay on a vendor BRMS may be significantly higher, with maintenance costs to match, open source tools have hidden costs that you must take into account in the comparison. OS tools are not as shrink wrapped as most vendor tools and will require internal support structures and wrapping code that will require internal maintenance. Teams to do this cannot yet be outsourced easily (the domain is, as yet, still a niche) and therefore this will need to be done onshore. Also vendors can do a lot for you that OS outfits cannot: a free proof of concept, free pre-sales consultancy and strong discounts – especially in the current economic environment. The cost of OS is also frequently undermined by the need to customise OS solutions to meet business need. Upgrade costs can also be significant as OS BRMS products are evolving more rapidly.
  2. Open Source BRMS Have the Same Functionality as Vendor Products: this is just not the case. In my years of experience using tools from both camps, vendor BRMS (from the market leaders) are still considerably more robust, more polished, more reliable and offer more functionality than OS equivalents. This is not to say that OS will never catch up, but it hasn’t yet. BRMS are, above all, are predicated on bringing understanding and control of business logic to the business – OS tools are just not much good at doing this yet: they do not offer seamless rule management by non-technical personnel – all too often technical details leak out, one only has to look at Drools error messages to see this. Also they offer poor vocabulary management facilities (compare Drools lexical substitution with JRules verbalisation concept, for example), no help with rule query or visualisation and little support for rule governance, security, testing and lifecycle issues. One the whole OS BRMS offer adequate functionality to support technical rules, but do not yet offer much hope for business rules.
  3. Open Source BRMS Have Equivalent or Better Support: again this is not true in my experience. OS developers tend to develop (and fix) what interests them, they have their own agenda. They often have little incentive to address the individual problems of clients. Vendors have a real incentive to support their clients, especially their big ones. They often have dedicated teams to do just this. The myth that OS offers millions of developers, all over the world, to support you, is disingenuous – these teams have much greater autonomy than you might like to believe and are frequently not very well trained with the products they are maintaining. Vendors may have much smaller teams, but they are trained and paid specifically to aid you in overcoming defects, some of them are often the authors of the software they are supporting.
  4. I Can Customise Open Source BRMS More Easily: clearly this is true from a literal perspective – because you have the source code. However the cost effectiveness of highly customised tools, tools that become, by degrees, unique to your organisation is questionable. The more you customise the less commoditised the product becomes and the harder it is to upgrade. Also, you must ask yourself what business are you in? Does an investment bank really have a good reason to be developing bespoke BRMS software?


So am I against OS BRMS? Of course not. It offers a very credible alternative to vendor products for maintaining technical rules within an IT team. Vendors ignore open source at their peril.

However for the mining, publishing and maintenance of business rules, by the business, vendor products are still the way to go – at least for the moment. For mixed requirements, the selection of vendor versus OS is still a nuanced decision that you will have to take carefully, ideally with the help of an experienced consultant.

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