Polar Has a Free API: The Open-Source Billing Platform That Lets You Monetize Your Developer Project in 10 Minutes

You built an open-source tool that thousands of developers use. Your GitHub repo has 2,000 stars. But your "Buy Me a Coffee" button generated $12 last year. The problem isn't that people don't want to support you — it's that existing monetization tools weren't built for developers. Polar was. What Polar Actually Does Polar is an open-source billing and monetization platform built for developers and OSS maintainers. Think Stripe plus GitHub Sponsors, with a developer-first API. It handles subscriptions, one-time donations, issue funding, and digital product sales. Polar is open-source (Apache 2.0), self-hostable, but their hosted platform at polar.sh charges zero monthly fee — just a small transaction percentage. The REST API uses OAuth2 or API keys. The critical difference from Patreon: Polar integrates with GitHub. Fund specific issues, reward contributors, automate benefits like private repo access for paying subscribers. Quick Start Get your API token from polar.sh Settings > Develo