StemJSON is a declarative language based on JSON, well-suited for AI to generate comprehensive, performant native app UI and logic - whether building new apps or extending existing ones.
The format is open. Drop it into AI tools, prototyping environments, IDE extensions, or alongside hand-written code to simplify and accelerate native app design, development, and delivery.
A sandboxed area inside your app where end users describe a feature in their own words - and the runtime renders a fully native module on the spot. Apps that adapt to each user, on demand.
An LLM emits StemJSON from the user's prompt; the runtime validates it, renders it natively, and keeps it inside the sandbox you defined. No new binary, no backend round-trip for the UI.
Patent pending.
User prompt
LLM
StemJSON
Native module
Other ways to use it
Server-driven UI
Push complete functional modules from your backend - state, actions, expressions, navigation, validation - straight to the device.
your server → StemJSON → device
Prototyping & design tools
From a prompt or a Figma export to a runnable native prototype. Tools emit StemJSON; the runtime renders it on-device - no glue code in between. Figma / AI tool → StemJSON → runnable app
Alongside hand-written code
Drop StemJSON modules into a native app for the parts that change often - settings, onboarding, content feeds - and keep the rest hand-written.