What is a Rules Engine and Why Use One? A Recap
In case you missed it! Here's what was discussed at last weeks Tech Thursday.
Introduction
We kicked off 2025 with a panel discussion with a fabulous technical panel, featuring:
Moderator: Oliver Hankinson, Chief Product Officer at Tacit Edge
Sergii Vershynskyi, Senior Cloud Engineer at Skip
Luca Chamecki Granato, Staff Software Developer at Neo Financial
Gavin Miller, Director of Application Security at Clio - Cloud-Based Legal Technology
The Calgary tech community gathered to explore what rules engines are, how they work, and their real-world applications. If you couldn’t make it, here’s everything you need to know!
From Left: Sergii Vershynski, Luca Chamecki Granato, Gavin Miller, and Oliver Hankinson.
What is a Rules Engine?
The panel began with the simplest of questions – which was (believe it or not) difficult to answer: What a rules engine is?
Here’s how our panelists broke it down:
Luca described it as a collection of rules used to build dynamic behaviours in a system. Think of it as a way to create workflows or pipelines where the whole is greater than the sum of its parts.
Gavin highlighted its role in externalizing business logic, enabling non-developers to interact with and modify rules without relying on engineering teams.
Sergii emphasized the importance of a rules engine in providing consistency. It follows a "condition-action" format: if a condition is met, a specific action is triggered. For instance, “If a credit score is below 600, deny a loan.”
Real-World Applications
Rules engines are everywhere. From fraud detection in credit card transactions to spam email filtering, they power decisions in real time. Examples included:
Fraud Prevention: Banks use rules engines to assess whether to approve or decline transactions based on risk factors like unusual spending patterns or location.
Workflow Automation: Legal firms, for instance, use rules engines to streamline onboarding, trust fund management, and compliance checks, adapting processes for specific practice areas.
Spam Filtering: Simple rules like "If the sender is unknown and the content includes certain keywords, move to spam" are at the heart of email filters.
Why Use a Rules Engine?
Empower Non-Technical Users: By externalizing logic, teams like compliance or risk management can directly update rules without engineering support.
Scalability: Rules engines handle thousands of rules efficiently, ensuring systems remain robust as complexity grows.
Flexibility: They adapt to frequent changes in business requirements, which would otherwise necessitate costly engineering overhauls.
Compliance and Transparency: Many rules engines provide detailed reporting and auditing, essential for meeting regulatory standards.
Challenges and Best Practices
Despite their benefits, implementing a rules engine isn’t without challenges:
Complexity: A system with millions of rules can become difficult to manage. Partitioning rules into logical groups and rigorous testing are essential.
Unintended Consequences: Rules can interact in unexpected ways, leading to unpredictable outcomes. Processes like peer reviews and historical data testing help mitigate risks.
Ethical Considerations: Rules engines must align with regulations like anti-discrimination laws. Review processes ensure rules don’t inadvertently introduce biases.
Panelists also discussed ethical dilemmas, such as when rules engines enforce compliance with international sanctions or detect fraudulent activity from specific regions. While necessary, these scenarios often involve trade-offs between fairness and business needs.
TL;DR
A rules engine is a tool for creating dynamic systems driven by “if-then” logic, enabling businesses to automate and streamline decision-making.
It democratizes rule creation, empowering non-technical users while keeping systems flexible and scalable.
Real-world examples, from credit card fraud prevention to legal workflow automation, highlight their versatility.
Ethical considerations and system complexity require careful oversight, but the benefits far outweigh the challenges.
Closing Thoughts
The panelists left us with a deeper understanding of the power of rules engines. Whether you're building workflows, detecting fraud, or automating spam filters, a well-implemented rules engine is a game-changer.
Have more questions or want to continue the discussion? Leave comments on this post!
Thank you to our incredible panelists—Oliver, Luca, Gavin, and Sergii —and to everyone who came out to the event.