# Build mobile, desktop, terminal, and device applications

One contracts can enter ordinary application frameworks without turning those
frameworks into One renderers. The APIs below are illustrative end-product
syntax; each application keeps its own root and generated projection receipt.

## SwiftUI client

```swift
struct OrderScreen: View {
    let client: OrdersClient
    let key: OrderKey
    @State private var state: ResourceState<OrderView> = .empty

    var body: some View {
        OrderContent(state: state)
            .task { state = await client.get(key) }
    }
}
```

SwiftUI owns navigation, view state, layout, accessibility, and lifecycle. The
generated client owns nominal values, operation calls, codecs, and dispositions.

## Rust terminal application

```rust,ignore
match client.get(&key)? {
    Success(order) => terminal.show_order(order),
    DomainFault(NotFound) => terminal.show_not_found(key),
    OuterCause(Denied) => terminal.show_access_required(),
    OuterCause(cause) => terminal.show_recovery(cause),
}
```

ParcelHub's current
[terminal presentation](https://github.com/muijf/one/blob/main/systems/system-idl/examples/parcelhub/src/orders_desk_terminal.rs)
owns executable evidence for exact generated dispatch and unknown-outcome
operator guidance.

## Intermittently connected device

```typescript
const result = await telemetry.append(batch, {
  cursor: retainedCursor,
  lease: selectedLease,
});

if (result.kind === "gapDetected") await resnapshot(result.oldestAvailable);
if (result.kind === "revoked") stopOfflineSubmission();
```

Offline capability is explicit and bounded. A disconnected device does not
retain online authority indefinitely or invent successful synchronization.

See [applications](/one/guides/applications) and
[Generate and use an SDK client](/one/examples/sdk-client).