Beyond orchestration: guardrail APIs that gate other systems' writes, automated payer remittance ingestion, automatic refunds and recoups, and the non-happy-path machinery (refilings, fee-schedule corrections, settled state that has to reopen and re-settle safely) where the real engineering difficulty lives. Nice to have: ledger, double-entry, invoicing, or reconciliation systems experience; healthcare billing or EDI exposure; fintech or payments background; experience through external audit or a financial close-cycle transition; has built simulation, shadow-mode, or backtesting infrastructure for consequential financial logic.