A business rules engine without redeploys

Context

A UK travel client priced products through dozens of business rules that changed weekly with the market. Each rule change meant a backend deploy, a QA cycle, and a release window. Operations teams had ideas they could not ship; engineering had a queue it could not drain.

The problem

Configuration-driven rule engines existed, but none expressed the conditional logic the business actually wrote. The product needed full expressive power — without giving non-engineers access to a code editor, and without paying the cost of a deploy for every change.

Approach

• Designed a compact rule grammar that operations teams could author from the admin UI.
• Built a service that took rules from the UI, compiled them into executable C# at runtime, and cached the resulting delegates per rule version.
• Made the evaluator run rules with the same performance profile as hand-written C#.

Outcomes

Time-to-market for new pricing rules

-90%

Deploys required for rule changes

Eliminated

Stack