Lago

Market position

Lago describes itself as the leading open-source pricing and billing solution for complex billing scenarios, and cites Product Hunt recognition and GitHub traction (10.4K stars on the main repository) as evidence of developer adoption. It competes against large closed platforms including Stripe Billing, Chargebee, Zuora, Adyen, Paddle, Salesforce and Zoho, as well as other open-source billing projects such as FOSSBilling, Kill Bill, jBilling and Open Source Billing. Its stated differentiation from incumbents rests on code inspectability, self-hosting and extensibility rather than dependence on a single vendor's roadmap, and on handling usage-based, subscription, prepaid and hybrid pricing in a single engine. Press coverage has framed the company as an open-source challenger to Stripe in billing.

Open-source, AGPLv3-licensed billing engine that customers can inspect, self-host and extend, positioned as a middle ground between third-party black-box vendors and homegrown billing systems. Lago is payment-agnostic — it keeps metering and pricing independent of the payment processor so a PSP's product catalog does not become the source of truth — and supports subscription, usage-based, prepaid and hybrid pricing on one engine. Additional differentiators cited include agent-accessible interfaces (MCP server, agent SDKs, OpenAPI schema) rather than dashboard-locked logic, flexible deployment (on-prem, VPC, cloud), and the Lago Embedded white-label model for platforms.

Technology

Event-based, real-time metering architecture designed to ingest events at scale while preventing duplicates, with six aggregation types converting raw events into billable metrics. The stack is API-first: a typed REST API with OpenAPI 3.1 schema, GraphQL schema in the API repository, bearer-token authentication with scoped and rotatable API keys, webhooks with delivery retries, idempotency keys and JWT or HMAC signature verification, and official client libraries in JavaScript, Python, Ruby, Go, PHP and Kotlin. The main repository is distributed via Docker Compose with API, front-end, connectors, deploy and events-processor components, and includes a runnable agentic-AI pricing demo. Agent-facing components include an MIT-licensed MCP server for reading and writing invoices, usage, customers, payments, credit notes and coupons, and Agent SDKs for Python and JavaScript/TypeScript that wrap LLM clients and emit token or model-cost events, with sub-5 ms p99 wrapper overhead claimed for the JS/TS SDK. Deployment options include on-premises, VPC and cloud, with role-based access control and SOC 2 Type II certification.

Go-to-market

Developer-led and open-source-led distribution: a free self-hostable AGPLv3 project on GitHub, public documentation, SDKs, Slack community and content marketing (blog posts on usage-based and AI agent pricing, comparison pages against competing billing platforms), converting into demo-booked sales for Lago Premium and enterprise deployments. Product Hunt launches and Hacker News visibility have been notable acquisition channels. Native integrations with Segment, Hightouch, Stripe Payments, Adyen and Salesforce extend reach within existing customer stacks, and Lago Embedded targets platforms that resell billing to their own users.

Engineering, product, finance and operations teams at technology companies with complex billing needs, including AI and LLM providers, enterprise software, fintech and embedded banking, IoT and telco, marketplaces and developer-tool platforms. Named customers and references include Mistral AI, PayPal, Groq, Swan, Synthesia, Together.ai, Juni and 1NCE.

Geography

Founded and originally based in Paris, France, with San Francisco listed as the company's location on its Y Combinator profile. Engineering hiring is advertised as remote across France, Spain, Germany, Portugal and Italy. The platform offers regional API base URLs and supports billing across multiple products and geographies.

History

Founded in 2021 out of Y Combinator's Summer 2021 cohort with a marketing automation product, Lago pivoted to billing after the Hacker News post about engineers' billing problems resonated. SignalFire first identified the company via Hacker News in early 2023 and reached out to its GitHub stargazers before investing. Lago was voted Product of the Day and Product of the Week on Product Hunt in April 2023, ran in closed beta with early customers including Mistral.ai, Together.ai and Juni, then launched officially on 14 March 2024 while simultaneously disclosing $22M raised across a $7M seed led by SignalFire and a $15M Series A led by FirstMark. The product line has since expanded into entitlements, revenue analytics, embedded white-label billing, and AI/agent-oriented tooling such as agent SDKs and an MCP server.

Risks & controversies

Billing is a highly crowded market, with competition from large incumbents such as Stripe, Adyen, Salesforce, Zoho and Paddle as well as several existing open-source billing projects, which press coverage identified as a central challenge. The company's own history includes an abandoned marketing-automation product that gained little traction before the pivot. Coverage also noted broader debate over how loosely the term "open source" is applied by commercially backed projects. Lago does not publish Premium pricing, and its AGPL-3.0 licensing may constrain some commercial redistribution use cases.