Privacy & how it works

MachineForge on the web is built the same way as our iOS apps: private by design.

Everything stays on this device

Your progress — best scores, XP and streak — is stored only in this browser (on-device storage). It is never sent anywhere. Clear your browser data and it's gone; nobody else can see it.

The lab and gear drill run right here

The mechanical-advantage lab and the gear-ratio drill are pure on-device math — the exact same formulas the MachineForge iOS app uses (effort ÷ load-arm for a lever, driven ÷ drive teeth for a gear, and so on). There's no server, no simulator in the cloud, and no AI that sees what you build.

No accounts, no ads, no tracking

There is no sign-up and no login. There are no ads and no in-app purchases. There are no third-party trackers embedded in the app.

Built for ages 9–14

The 400 concept questions come straight from the MachineForge iOS project and are aligned to NGSS engineering-design and simple-machines standards. A hint appears only after a first try — you think it through first, and mistakes are treated as part of learning. The iOS app also has a hands-on physics sandbox (build a catapult, knock down a tower) that needs a phone's physics engine — that part stays on iOS; the web version focuses on the reasoning and the math.

Spark & Anvil is a 501(c)(3) public charity. Apps stay free forever. This page is a plain-language summary, not legal advice.

Meet the cast Full parent guide Site privacy policy