Polar.sh is an open-source billing platform for developers launched in 2023. It positions itself as a Merchant of Record that handles payment processing, tax compliance, and digital product delivery for SaaS and developer tools.

Polar supports subscriptions, one-time purchases, usage-based billing, and automated entitlements like license keys. The platform offers recurring plans with trials, upgrades, proration, and dunning built in. Free or paid trials with automatic conversion, reminders, and grace periods are available. Coupons, promo codes, and volume tiers can be configured. The new free Starter plan costs 5% + 50 cents per transaction, and to get lower rates you must subscribe to a paid plan (Pro at $20/mo, Growth at $100/mo, or Scale at $400/mo). International card surcharges still add 1.5%. The platform became an official GitHub funding partner in 2024 and has attracted notable users including Tailwind Labs and Midday. Polar is open source, licensed under the Apache 2.0 license.
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