head to head · open source
Lago vs Polar
Lago has 10,568 GitHub stars, 750 forks, 23 open issues and last shipped yesterday. Polar has 10,270 stars, 787 forks, 141 open issues and last shipped yesterday. Lago leads on adoption by 3% (10,568 vs 10,270 stars). Lago is written in Go under AGPL-3.0; Polar is written in Python under Apache-2.0. Lago has attracted 7% as many forks as stars, Polar 8%. Polar was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (payments), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Lago | Polar | |
|---|---|---|
| GitHub stars | ★ 11K | ★ 10K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Go | Python |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 750 | ⑂ 787 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Lago if
- You weight community size — 11K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick Polar if
- You want the Polar feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and Polar fits your workflow better
About Lago
Lago is an open source metering and usage based billing API written in Go under AGPL 3.0. It lives in the Business Software and Finance & Accounting ecosystem and sits between product usage and revenue. It turns events such as AI tokens, compute, API calls, seats, and custom events into billable metrics, pricing, credits, entitlements, invoices, and payments.
About Polar
Polar is an open source billing platform and payment infrastructure project for digital products, SaaS applications, and AI workloads. It is written in Python, licensed under Apache 2.0, and built around FastAPI, Next.js, React, and Turborepo. The project positions itself as a financial layer for software that needs to charge for tokens, agents, compute, subscriptions, and usage based models.
read the full Polar overview →
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Frequently asked questions
Is Lago or Polar more popular?
Lago has 10,568 GitHub stars and Polar has 10,270. Lago has the larger community by that measure.
Are Lago and Polar free?
Both are open source. Lago is licensed under AGPL-3.0 and Polar under Apache-2.0. Neither carries a licence fee.
What is the difference between Lago and Polar?
Lago is written in Go and Polar in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Lago or Polar?
Choose Lago if you want the larger community (10,568 stars) or its AGPL-3.0 licence terms. Choose Polar if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.