Is the SDK available today?

It's in public beta. Email hello@foundation.xyz with the subject "Prime SDK feedback" to get in touch with the team.

Do I need a Prime device to start?

No. The hosted simulator (foundation sim) lets you build and test without hardware. You only need a device when you're ready to validate against real peripherals.

What language do I write apps in?

Rust. UI is Slint .

Can I sideload apps today?

Yes. Build an .elf, copy it to the device via USB mass storage to apps/<app-name>/app.elf, and reboot. No store review required. See Get Started - Sideloading .

Will there be an app store?

Yes - an opt-in catalog for discovery is on the roadmap. Sideloading will always remain available. No walled gardens.

What are the licensing terms?

KeyOS is open source. Your app can be any license you choose. Distribution terms for the upcoming catalog are TBD - email us if it matters for your decision.

How do I sign my app?

Every app on Prime is signed with cosign2 (secp256k1 + self-signed X.509 code-signing cert). Generate a signing identity once with foundation cert gen "<Your Name>", then foundation build will pick it up automatically. See Building Apps — Signing for the full flow.

Where is my signing key stored?

Under ~/.foundation/signing/<identity>/. private.pem is the secp256k1 private key — keep it secret and back it up. Losing it means you cannot push updates under the same identity.

Can I use one signing identity for multiple apps?

Yes. Your signing identity is per-publisher, not per-app. Multiple apps can reference the same identity via signing-identity in their app-config.toml.

Does my app get internet access?

No. Prime is intentionally offline. All comms go through user-mediated channels: USB-C, NFC, camera, QuantumLink Bluetooth. See Capabilities - Why no network?

How do I declare which hardware my app uses?

In manifest.toml, via per-service permission lists. The kernel enforces the declared set at runtime - there is no runtime escalation. See Building Apps - The manifest .

Can my app access the user's Bitcoin seed?

Only if the user explicitly grants it via os/security permissions and confirms on the trusted display. Seeds never leave the secure element unencrypted.

Is there a public sample apps repo I can clone?

🚧 Coming soon. A public foundation-devices/prime-examples repo with small, focused starter apps is in preparation. Until then, the in-house apps in the KeyOS repo are the best reference implementations.

Where do I report bugs or get help?

hello@foundation.xyz during public beta. Dedicated public dev channels (community forum, GitHub issue tracker) are coming soon.

I want to build a wallet - anything special I should know?

Yes. Email hello@foundation.xyz for our security review checklist before you ship. Anything that touches keys gets extra scrutiny, and we'd rather help you get it right than catch problems after launch.