nosmai_moderation_sdk

On-device content and text moderation for Flutter, powered by the native Nosmai SDK. It detects NSFW content (nudity and suggestive) in images, videos, and a live camera feed, and it moderates chat text for toxicity. Everything runs fully offline. No frame or message leaves the device.

Features

  • Image moderation: an NSFW verdict per image.
  • Video moderation: samples frames and aggregates a verdict.
  • Live camera moderation: a native preview with per-frame results.
  • Text moderation: chat toxicity using a keyword layer and an AI classifier.
  • Selective model loading: load only the models you use.
  • Runtime NSFW threshold tuning.

Requirements

  • iOS 15.1 or later, Android 7.0 (API 24) or later.
  • An arm64-v8a Android device (the SDK ships arm64 only).
  • Kotlin 2.2.0 or later in the Android host app.
  • A Nosmai license key. Register your app's bundle id (iOS) and package id (Android) at https://nosmai.com/.

Installation

Add the plugin:

flutter pub add nosmai_moderation_sdk

The native SDK is not bundled inside this plugin because it is large. Each platform pulls it from its own published channel.

iOS

No extra steps. The plugin depends on the NosmaiModerationSDK CocoaPods pod, so pod install (run automatically by flutter run) downloads the native SDK, links it, and bundles the encrypted models. Add these keys to your app's Info.plist:

  • NSCameraUsageDescription: a usage string, required for the live camera.
  • ITSAppUsesNonExemptEncryption set to false: the SDK uses AES only to decrypt its own models on device, which qualifies for the export-compliance exemption. Confirm with your legal team.

Device builds are arm64. Apple-silicon simulators are supported. Intel-Mac simulators are not.

Android

The Android SDK ships as a downloadable AAR because it is too large for pub.dev. Add it to your app module:

  1. Download nosmai-detection.aar from the Android SDK releases and place it at android/app/libs/nosmai-detection.aar.
  2. In android/app/build.gradle.kts: 
    android {
    defaultConfig {
        minSdk = 24
        ndk { abiFilters += "arm64-v8a" }
    }
}
dependencies {
    implementation(files("libs/nosmai-detection.aar"))
}
  3. Distribute as an App Bundle (AAB). The SDK is arm64-v8a only, so test on a real device, not an x86_64 emulator.
  4. Request the CAMERA permission at runtime before starting the live camera, for example with the permission_handler package.

Usage

import 'package:nosmai_moderation_sdk/nosmai_moderation_sdk.dart';

// Initialize once at startup. Load only the models you need.
final init = await NosmaiModeration.initialize(
  'NOSMAI-XXXX',
  models: [NosmaiModel.nsfw],
);
if (init.success != true) {
  print('Moderation unavailable: ${init.error}');
}

// Image (NSFW verdict).
final image = await NosmaiModeration.analyzeImage(file.path);
if (image.isUnsafe == true) {
  // image.nsfw for SAFE / WARN / BLOCK.
}

// Recorded video.
final video = await NosmaiModeration.analyzeVideo(file.path, frameIntervalMs: 500);

// Chat text (optional model).
await NosmaiModeration.initializeText();
final text = await NosmaiModeration.moderateText('a message to check');
if (text.blocked == true) {
  print('blocked: ${text.category}');
}

// Tune the NSFW threshold at runtime.
await NosmaiModeration.setNsfwThreshold(NosmaiNsfwClass.explicit, 0.45);

// Free native resources when done.
await NosmaiModeration.shutdown();

Live camera

Show NosmaiCameraPreview, start the camera, and listen to results. Call NosmaiLive.stop() when leaving the screen (for example in dispose). The camera does not stop itself on widget disposal.

@override
void initState() {
  super.initState();
  NosmaiLive.start(facing: NosmaiCameraFacing.back);
  _sub = NosmaiLive.results().listen(
    (r) { /* r.isUnsafe, r.nsfw */ },
    onError: (e) { /* camera failed to start */ },
  );
}

@override
void dispose() {
  _sub.cancel();
  NosmaiLive.stop();
  super.dispose();
}

// In build():  const NosmaiCameraPreview()

Request the camera permission before opening the live screen. On Android the preview stays blank if the permission has not been granted.

How it works

The camera, frame capture, and detection all run natively for performance. Only the per-frame result crosses to Dart. The request and response APIs (image, video, text) use Pigeon for type-safe messaging. The live camera uses a method channel for start and stop, and an event channel for per-frame results. Models are encrypted and decrypted in native memory.

License

Proprietary. See LICENSE. To get a license key, register your app at https://nosmai.com/.

Libraries

nosmai_moderation_sdk