Keylight vs Polar.sh — licensing, not billing

Polar.sh and Keylight get mentioned together, but they don’t overlap — they’re two halves of the same stack. Polar takes the money, meters the usage, and handles the tax. Keylight decides who gets to run your app, on which machines, for how long. You probably want both.

What Polar.sh gets right

Polar is modern, developer-first billing. It’s a merchant of record, so it charges customers and handles worldwide tax for you. It’s strong where the new wave of software is heading: usage-based billing — tokens, API calls, compute — plus subscriptions, credits, and seats. The AI-native angle is real; it’s built for token-metered APIs and agents, and it shows. For getting paid, especially on usage, Polar is a sharp choice.

It can also attach a license key to a purchase. For a simple unlock, that can be enough.

Where Keylight is different

Polar is billing-first. The licensing is a benefit on the invoice, not the product.

A real app license is more than a key in a receipt. It’s a device limit that’s enforced. It’s an offline check so the app works with no network. It’s a trial that converts, a Pro tier you gate, a key you revoke after a refund. Polar doesn’t do those. Keylight does — it’s the whole licensing half:

await licensing.checkOnLaunch()
if licensing.state == .licensed { enablePaidFeatures() }

Offline checks run on Ed25519-signed leases verified locally. Feature flags ride in the lease. Device activations are tracked server-side and enforced. The Swift SDK handles activation, trials, and expiry as a state machine.

How they fit together

You don’t pick one. Bill with Polar, license with Keylight. Stripe is the first-class path — a charge mints the license automatically with no webhook code. Other payment providers, Polar included, connect by webhook: Polar handles the sale, the usage, and the tax, then tells Keylight to issue the license.

This pairing is especially clean for AI apps — Polar meters the tokens, Keylight licenses the app. More on that in licensing for AI apps.

Where Keylight fits

Shipping a Mac or Swift app that needs real licensing — not just a key on the invoice? That’s Keylight. Swift SDK, offline leases, device limits, feature flags. Bring whatever payment provider you like for the money, Polar included.

Plans start at $19/month, with a free tier. Keep your biller. Add real licensing.