SDKs

One integration, five platforms

The SDKs are open-source and ship in this repository. Public registry releases (npm, pub.dev, Maven Central, SPM, NuGet) are planned but not shipped yet — today you vendor via a local path or project reference.

Beta · local source only

Source lives in this repo as @ctrlapp/sdk. No public npm release yet — vendor via the documented local path.

Install (local)

// package.json
"@ctrlapp/sdk": "file:../packages/ctrl-sdk"

Web controls docs →Web integration →

Initialize · read · track

import { Ctrl } from "@ctrlapp/sdk";

const ctrl = Ctrl.init({
  apiKey: "ck_sdk_...",
  deviceId: getOrCreateDeviceId(),
  platform: "web",
});

await ctrl.register();      // ensures the device exists server-side
await ctrl.load();           // resolved controls map
ctrl.startPolling();         // background refresh (default 60s)

if (ctrl.flag("checkout_v2").isOn) showNewCheckout();
ctrl.track("checkout_v2", "impression");

See full docs for per-type reads, streaming, and offline behavior.

Behavior

Same contract, platform-appropriate lifecycle

Aspect	Web / .NET	Flutter / iOS / Android
Sync cadence	Poll (default 60s) + SSE stream when supported	Poll + SSE stream; app foreground triggers refresh
Offline cache	Browser localStorage / on-disk JSON	Platform-native persistent store
Screen capture	Best-effort visual mask	OS-level (FLAG_SECURE / iOS masking)
Public REST endpoints	/register, /session, /sync, /controls (+ delta / SSE stream), /controls/events, /flags/ruleset, /flags/impressions

Vendor the SDK, create an account, ship a control.

Each SDK exposes a small, identical surface: initialize, read a flag, track an event.

Create account Open the docs