What Polar does
Polar is an open-source billing platform that acts as merchant of record for software sellers. It handles checkout, subscriptions, usage-based billing, credits, and global sales tax through one API.
Polar is a billing and payments platform for developers who sell software, with a focus on AI products. It meters usage, runs subscriptions and invoicing, and sells to your customers as the merchant of record. That means Polar acts as the reseller of your product in more than 100 markets and takes responsibility for payments, sales tax, fraud, refunds, and chargebacks.
The platform is built from a few billing primitives that you can combine on one product. Usage billing ingests events such as tokens, API calls, compute time, and storage and rolls them into live meters for each customer. Subscriptions support trials, upgrades, and proration. Credits are prepaid balances that draw down with usage. Seat-based and unit-based pricing, discounts, and custom checkout fields are also available, and Cost Insights compares inference cost with revenue to show gross margin per customer.
Customers pay through a hosted checkout with localized currencies and tax included, which you can share as a link or embed on your site. Automated benefits can grant license keys, file downloads, Discord roles, private GitHub repository access, or feature flags after a purchase. Revenue is paid out to your bank account.
Developers integrate through the Polar API, typed Python and TypeScript SDKs, framework adapters, and webhooks. A remote MCP server with OAuth lets AI agents manage products, customers, subscriptions, and orders. The source code is on GitHub under the Apache 2.0 license.
Pricing is published openly. The Starter plan has no monthly fee and charges 5% + 50¢ per transaction. Pro costs $20 per month at 3.8% + 40¢, Growth $100 per month, and Scale $400 per month at 3.4% + 30¢, with a 1.5% surcharge for international cards. Polar Software, Inc. is a small remote team backed by venture firms and angel investors.
Best for
Developers and small software teams, especially AI startups, that want subscriptions, usage-based billing, and global tax compliance without building billing themselves.
Not for
Sellers of physical goods, or companies that want to be their own merchant of record and handle tax registrations directly.
Questions and answers
What does merchant of record mean at Polar?
Polar acts as the reseller of your product in over 100 markets. Payments, sales tax, fraud, refunds, and chargebacks are its responsibility.
How much does Polar cost?
Starter is free with 5% + 50¢ per transaction. Pro is $20 per month at 3.8% + 40¢, Growth $100 per month, and Scale $400 per month at 3.4% + 30¢.
Can Polar bill for AI usage?
Yes. You ingest events such as tokens, API calls, or GPU time, aggregate them into meters, and the usage is billed on each customer's invoice.
Is Polar open source?
Yes. The Polar source code is public on GitHub under the Apache 2.0 license.
Can AI agents manage my Polar account?
Yes. Polar runs a remote MCP server that uses OAuth, so agents can manage products, customers, subscriptions, and orders.