Welcome to the Keylight blog

Welcome to the Keylight blog.

What Keylight is

Keylight is licensing infrastructure for apps. Stripe handles payments; Keylight mints, signs, and verifies the licenses your app reads at runtime — including offline, with Ed25519-signed leases that work in a tunnel or on a plane.

Here’s the kind of code the SDK lets you write inside an app:

import KeylightSDK

await licensing.activate(key: enteredKey)

if case .licensed = licensing.state {
    showProFeature()
}

The example is Swift, the most mature SDK — but the same activate / state-machine API ships for Rust and JavaScript/TypeScript too.

What this blog is for

This is where we write down what we learn building it: how license keys actually work for desktop apps, how to avoid the most common scaling traps, and how to compare the options when you outgrow the App Store or a Merchant-of-Record platform.

Posts are written for developers shipping paid desktop and AI-native apps — Swift-first, with Rust and JavaScript/TypeScript too — outside the App Store, and for anyone evaluating the licensing infrastructure layer between Stripe and their app.

Send us topics

We don’t have a content calendar set in stone. The most useful posts are the ones answering questions real builders are asking — what broke when their license server went down, what they wish Paddle had told them, how they handle refunds on a desktop app.

If you have a topic you’d like covered, send us your feedback. Every suggestion is read; most get answered the same week.