What is Polar used for?

Polar is a billing platform for software and AI products that handles usage-based pricing, subscriptions, checkouts and tax as merchant of record. It is a good fit for charging AI apps per token or agent run and selling subscriptions without handling VAT yourself.

Is Polar open source?

Yes. Polar is open source under the Apache-2.0 licence. Its source code is on GitHub at polarsource/polar and is written mainly in Python.

Yes. Polar is open source, so the software itself is free to use. A managed cloud version is also available, with paid plans from $20 per month.

Can I self-host Polar?

Yes. Polar can be self-hosted on your own server or infrastructure.

What is Polar an alternative to?

Polar is an open-source alternative to Lemon Squeezy, Paddle, Gumroad and Stripe Billing. Other open-source alternatives to Lemon Squeezy include Easy Digital Downloads.

Is Polar actively maintained?

Yes. The most recent commit to Polar was on 2 October 2026. The project has 10k stars on GitHub.

Polar: open-source alternative to Lemon Squeezy, Paddle

About Polar

Polar is an open-source billing platform aimed at AI startups and other software businesses that need to charge for tokens, agents and compute without building billing infrastructure themselves. It positions itself as the financial layer for intelligent software and acts as the merchant of record.

It supports many pricing models, including usage billing, subscriptions, seats, credits, trials and discounts, which can be combined. Metering can track tokens, API calls, agent runs, GPU seconds and storage at the level of individual events. Checkouts, real-time metrics and worldwide tax handling are included, and as merchant of record Polar takes on receipts, customer accounts, dunning, sales tax and VAT.

Polar is built with Python and FastAPI on the backend and Next.js, React and TypeScript on the frontend, in a Turborepo monorepo, and is licensed under Apache-2.0. An API and SDKs let you integrate it into docs, sites and services. Pricing is per transaction, and an application-based Startup Program is available for eligible startups.

Key features

Usage-based billing and metering
Subscriptions, seats, credits and trials
Checkout flows with real-time metrics
Merchant of record with tax handling
Python and TypeScript SDK integrations

Good fit for

→Charging AI apps per token or agent run
→Selling subscriptions without handling VAT yourself

Built with: Python; FastAPI; Next.js; TypeScript; React
Tags: billing; payments; subscriptions; usage-billing; merchant-of-record; saas; fastapi; ai

Polar: questions and answers

What is Polar used for?: Polar is a billing platform for software and AI products that handles usage-based pricing, subscriptions, checkouts and tax as merchant of record. It is a good fit for charging AI apps per token or agent run and selling subscriptions without handling VAT yourself.
Is Polar open source?: Yes. Polar is open source under the Apache-2.0 licence. Its source code is on GitHub at polarsource/polar and is written mainly in Python.
Is Polar free?: Yes. Polar is open source, so the software itself is free to use. A managed cloud version is also available, with paid plans from $20 per month.
Can I self-host Polar?: Yes. Polar can be self-hosted on your own server or infrastructure.
What is Polar an alternative to?: Polar is an open-source alternative to Lemon Squeezy, Paddle, Gumroad and Stripe Billing. Other open-source alternatives to Lemon Squeezy include Easy Digital Downloads.
Is Polar actively maintained?: Yes. The most recent commit to Polar was on 2 October 2026. The project has 10k stars on GitHub.