Two engines you can drive in your browser and read on GitHub, plus a short warm-up playground. Both engines are open source (MIT), implemented twice (.NET 10 and JavaScript), pinned by hand-written shared cases and compared field by field in CI. Judge the engineering before you talk to us.
Commercial invoice ↔ packing list ↔ bill of lading. 21 rules, integer arithmetic, every finding explained. Edit any field and watch which rule catches it.
Seven customs documents, six roles, SLAs, a reconciliation gate, an ERP outbox and a closure rule — event-sourced, replayed on every click, every refusal explained.
A lighter, guided demo: a purchase request, four rules, five scenarios you can finish in three minutes. Start here if you have never seen a rules-driven approval flow.