Rating Engine — Applies the price plan to metered usage — tiers, volume breaks, minimums, credits — turning quantities into charges. It consumes aggregated usage and entitlement context, and its rated output becomes the line items invoice generation assembles.
Where it sits in the lifecycle
Rating Engine lives in the Rate & Bill phase
of Fulfill & Bill — the stage where you activate what was sold, meter what's used, bill it right.
In the corpus tool index this phase maps to the Billing and Paymentscategories.
Tools that support it
Companies whose monetization signals name each tool, of the rating engine supporters — from public job posts, blogs, and filings.