Polar

Open-source billing infrastructure for monetizing software. Handles payments, usage-based billing, subscriptions, and one-time purchases while acting as Merchant of Record for global tax compliance, so developers can sell worldwide without managing VAT, GST, or sales tax.

Polar is used by Tailwind, Speakeasy, Stilla AI, Midday, and endorsed by Vercel, Dub, and Ghostty. It differentiates from payment processors like Stripe by bundling full billing infrastructure: product management, automated benefit delivery, and tax handling in one stack.

Key features:

• Usage billing with event ingestion for API calls, token consumption, and custom metrics
• Automated benefit delivery for license keys, file downloads, GitHub repository access, and Discord roles
• Global Merchant of Record handling international tax compliance across jurisdictions
• Framework adapters for Next.js, BetterAuth, Laravel, Deno, Remix, Fastify, Hono, and others
• SDKs for TypeScript, Python, Go, and PHP with webhook support

Developers integrate Polar to sell digital products, SaaS subscriptions, or usage-based API access. The platform suits AI companies metering token usage, indie devs shipping license keys, and teams offering Discord or GitHub gated access. Checkout links work without code; embedded checkout and full APIs support custom flows.