Open-source Metering & Usage-based Billing API
"Lago is an open-source software for metering and usage-based billing.
It’s the best alternative to Chargebee, Recurly or Stripe Billing for companies that need to handle complex billing logic. This library will allow you to build an entire billing system from scratch. Lago is a real-time, event-based solution made for usage-based billing, subscription-based billing, and all the nuances of pricing in between.
You can use the self-hosted version to deploy Lago on your existing infrastructure or request access to Lago Cloud to start using our solution immediately.
The admin UI of Lago is built using React and TypeScript."