Polar

Polar is a merchant of record billing platform built for developers and, in particular, for usage-based AI products: it meters raw usage events such as tokens, API calls, compute, and storage, and automatically converts them into invoiceable charges through a single integration. Like Paddle and Lemon Squeezy, Polar acts as the reseller of your product in over 100 markets, taking on payments, sales tax, fraud, refunds, and chargebacks. The compliance argument is the same as any merchant of record: you stop being the legal seller, so you stop owning global tax registration and filing. What differentiates Polar is the metering layer sitting on top of that. It describes itself as the billing stack for the intelligence era, and it is designed around the problem that AI products bill on consumption that is expensive to measure and awkward to reconcile. Pricing has a genuinely free entry point and falls as you scale. Starter costs nothing monthly and charges 5.00% + 50 cents per transaction. Pro is $20/month and charges 3.80% + 40 cents. Growth is $100/month and charges 3.60% + 35 cents. Scale is $400/month and charges 3.40% + 30 cents. Because the monthly fee buys a lower rate, the correct tier is a straightforward arithmetic question rather than a feature question: work out the volume at which the monthly fee is recovered by the reduced percentage and move up at that point. That descending structure is the clearest practical difference from Paddle, which charges a flat 5% + 50 cents at every volume with no monthly fee. Below roughly a few thousand dollars of monthly revenue, Polar's free Starter tier and Paddle are effectively the same price. Above that, Polar's paid tiers get cheaper and Paddle does not. Who it is for: developers shipping API products, AI tools, and SaaS with consumption-based pricing, especially solo founders and small teams who want metering, subscriptions, invoicing, and payouts from one integration rather than assembled from a processor plus a metering service plus a tax engine. How it compares: Stripe is the most flexible and cheapest per transaction but is not a merchant of record, so global tax stays your problem. Paddle is more mature, with deeper subscription billing and a longer compliance track record, at a flat and eventually higher rate. Lemon Squeezy, now Stripe-owned, is the lightest option for straightforward digital product sales but is less oriented toward metered usage. Polar's advantage is being the merchant-of-record option that treats usage metering as a first-class primitive and prices down with scale; its disadvantage is being the youngest of the group, with the shortest operating history behind it. Evaluate it if you are billing for consumption and do not want to build the meter yourself.