Lago

Lago is a Paris-based open-source billing platform for usage-based and subscription pricing, founded in 2021 and backed by Y Combinator and FirstMark. The platform handles event metering, plan/pricing iterations, automatic invoice generation, prepaid credits, coupons, add-ons, multi-currency support and revenue analytics, with a developer-first API. The self-hosted edition is free under AGPL/Lago licence; Lago Cloud and a Premium edition (with SSO, audit logs and priority support) are paid SaaS plans.