Is a Workflow Engine the Same as a Business Rule Engine?

Manish Nepal

August 17th, 2017 workflow  

Many people think that workflow engine and business rule engine are the same. Some even use the terms workflow engine and business rule engine interchangeably. But they are actually quite different terms, and you can run into a lot of headaches if you don’t know which one you are looking for.

Workflow Engine

Let’s clear the fog around the two terms by looking at some real-world differences in their usage.

What is a Workflow Engine?

A workflow is a series of tasks that process data to a finished state. It’s a time-bound orchestration of tasks that are repetitive and predictive in nature.

When you buy a pair of jeans from your favorite online store, it kickstarts a workflow involving payment processing, order fulfillment, and dispatching to delivery.

Here’s an example of a workflow process looks when depicted in a visual workflow editor.

Processbuilder

Most workflows are manually completed and carried out through email or paperwork for approval. But in recent years, modern businesses have used workflow software to automate their workflows for speed, accuracy, and cost efficiency.

Most of these tools come hard-coded with a process designer, a feature that allows software users to run a workflow instance without coding. The workflow designer lets the admin route tasks in a linear sequence, assign tasks dynamically depending on data in the form, and add conditions, exceptions, parallel branches, etc.

So where does the workflow engine come in?

In this context, a workflow engine is a pre-coded script that takes account of a workflow design, i.e. how tasks should flow from one stage to another, and executes the step. A workflow engine is a code embedded in the software that pushes a task from one stage to another.

Notice that the workflow engine doesn’t influence ‘how’ a workflow should take place, but takes its cue from the design and runs the tasks.

What is a Business Rule Engine?

A business rule engine is a set of conditions in a software that executes an application code if all (or a specified number of) conditions are met. It is about setting criteria for how a software should behave within certain parameters.

The advantage of a rule engine is that it enables non-technical software users to change the software behavior based on their business requirements without having to change the underlying codes. They make decision-making quick and reliable based on a multitude of facts that is too large for humans to process through.

Business rule engines (referred to as BRE in enterprise parlance) are part of a broader concept that finds its scope outside of a workflow management. Rule engines have no control over orchestrating tasks; they work like a guideline for a software to infer decisions based on certain criteria. It can be used to emulate a workflow process given the conditions.

Here’s an example of how an e-commerce website can have one of the following rule engines applied to its payment gateway:

  • Apply 15% youth discount on the item if the buyer enters age 18 to 29.
  • Apply 20% discount on the item if the buyer chooses his age >59.
  • Apply no discount on the item if the buyer chooses age between 30 to 59.

A set of business rule engines combined together is called ruleset; they are often represented in tabular form or a decision tree. Enterprise software uses business rule engines mainly to ensure operational consistency.

How Are Workflow Engines and Business Rule Engines Different?

A workflow engine and business rule engine both allow non-techy end-users to change a process behavior at runtime without the need to change the code.

But they have more differences than similarities. As mentioned above, they are fundamentally different in their working and purpose. Listed below are a few more differences between a workflow engine and a rule engine: 

Workflow Engine

Business Rule Engine

A program designed to run workflow instances based on the process model A program designed to help with complex decision-making
A component specific to a workflow technology A component of an enterprise application
Inherent driving force in an automated workflow Works as a pluggable element that could be separated from the application code
Help with carrying out a business process Help with creating business knowledge
Is based on process design Is rules-driven

The Conclusion

As easy as it is to mix up workflow engine with business rule engines, they are wildly different concepts with different purposes – which is important to keep in mind when you’re looking for workflow or BPM software.