Lago ranks #7 in Payments & Fintech APIs AI search.

Lago is an open-source billing infrastructure platform founded in Paris in 2021 and backed by Y Combinator, FirstMark Capital, and SignalFire. It provides engineering and finance teams with a programmable API and visual interface to manage complex pricing models including usage-based, subscription, hybrid, and enterprise custom contracts. Lago's AGPLv3-licensed codebase can be self-hosted for full data control or consumed as a managed cloud service. The platform covers the full billing lifecycle: event ingestion and real-time metering, plan configuration, automated invoicing, prepaid credits, entitlements, cash collection, and revenue analytics. Customers include Mistral AI, PayPal, Groq, Arcee AI, and 1NCE. Lago processes approximately $829 million in invoices monthly.

Lago is an open-source, API-first billing platform designed to handle complex, hybrid, and usage-based pricing models at scale. It combines a programmable metering engine, plan and subscription management, automated invoicing, entitlements, cash collection, and revenue analytics in a single system. It is payment-agnostic and can be deployed on Lago Cloud or self-hosted, giving companies full transparency and control over their billing infrastructure.