Open-source billing engine for AI products — token metering with model × token_type matrix pricing, prepaid commits + drawdown, per-customer margin/COGS. Self-hosted in your VPC.
A production-grade, dependency-free Go SDK for the entire [Xero](https://developer.xero.com) API platform — Accounting, Assets, Files, Projects, Bank Feeds, Finance, Practice Manager, App Store, eInvoicing, and Payroll (AU/NZ/UK).