DuckCMP — Open Source Consent Management SDK for Android & iOS

Features

Everything you need

Built for real apps. No bloat, no third-party dependencies, just clean native code.

🎨

4 Layout Options

Banner, popup, fullscreen, or bottom sheet. Pick the presentation that fits your UX.

🌈

Full Theming

Colors, corner radius, overlay, button styles. Match your brand perfectly with ConsentTheme.

🛠

Custom Categories

Define your own consent categories with names, descriptions, and required flags. 4 sensible defaults included.

🌐

WebView Bridge

The __duckcmp JS interface lets web content read and write consent. Full bidirectional sync.

🔒

Require Consent

Force users to make a choice before proceeding. Blocks back button, overlay dismiss, and swipe-to-close.

⚡

Two Native SDKs

Pure Kotlin for Android, pure Swift for iOS. Compose & SwiftUI. Zero cross-platform overhead.

Defaults

Default Categories

4 built-in consent categories. Rename, reorder, add, or remove them via ConsentConfig.

ID	Category	Description	Required
1	Necessary	Essential for the app to function. Cannot be disabled.	Required
2	Analytics	Help us understand how you use the app.	Optional
3	Marketing	Used to deliver personalized ads.	Optional
4	Preferences	Remember your settings and choices.	Optional

Presentation

Layout Options

Set via ConsentConfig(layout: ConsentLayout.POPUP)

Banner

Compact bottom bar. Non-intrusive. Expands on "Manage".

Popup

Classic centered modal. The default. Balanced visibility.

Fullscreen

Takes over the screen. Maximum attention. Great with requireConsent.

Bottom Sheet

Draggable sheet covering ~85%. Scrollable. Buttons pinned.

Quick Start

Up and running in minutes

Three steps to add consent management to your app

1

Add the dependency

Gradle
// settings.gradle.kts — add GitHub Packages repo
dependencyResolutionManagement {
    repositories {
        maven {
            url = uri("https://maven.pkg.github.com/analytics-debugger/duckcmp")
            credentials {
                username = providers.gradleProperty("gpr.user").orNull
                    ?: System.getenv("GITHUB_ACTOR")
                password = providers.gradleProperty("gpr.key").orNull
                    ?: System.getenv("GITHUB_TOKEN")
            }
        }
    }
}

// app/build.gradle.kts
dependencies {
    implementation("com.analytics.debugger:duck-cmp:0.0.1-alpha")
}

2

Initialize & configure

Kotlin
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // Initialize with defaults (4 categories, popup layout)
        DuckCMP.initialize(this)

        // Or fully customize
        DuckCMP.initialize(this, ConsentConfig(
            dialogTitle = "Your Privacy Matters",
            dialogMessage = "Choose which data categories you allow.",
            layout = ConsentLayout.BOTTOM_SHEET,
            requireConsent = true,
            buttons = listOf(
                ConsentButton.SAVE_CHOICES,
                ConsentButton.ACCEPT_ALL,
                ConsentButton.REJECT_ALL
            ),
            theme = ConsentTheme(
                primaryColor = 0xFF6200EE,
                cornerRadius = 16f
            )
        ))
    }
}

3

Show the dialog & check consent

Kotlin
// Show the consent dialog
DuckCMP.showConsentDialog(activity)

// Check if a category is consented
val hasAnalytics = DuckCMP.hasConsent(2)   // Analytics
val hasMarketing = DuckCMP.hasConsent(3)   // Marketing

// Get overall status
val status = DuckCMP.getConsentStatus()   // UNKNOWN, ACCEPTED, REJECTED, PARTIAL

// Listen for changes
DuckCMP.addCallback(object : ConsentCallback {
    override fun onConsentGiven(result: ConsentResult) { /* user chose */ }
    override fun onConsentRevoked() { /* consent reset */ }
    override fun onDialogDismissed() { /* dialog closed */ }
})

1

Add the package

Swift Package Manager
// Xcode: File > Add Package Dependencies
// URL: https://github.com/analytics-debugger/duckcmp

// Or in Package.swift:
.package(url: "https://github.com/analytics-debugger/duckcmp", from: "0.0.1-alpha")

2

Initialize & configure

Swift
import DuckCMP

@main
struct MyApp: App {
    init() {
        // Initialize with defaults
        DuckCMP.initialize()

        // Or fully customize
        DuckCMP.initialize(config: ConsentConfig(
            dialogTitle: "Your Privacy Matters",
            layout: .bottomSheet,
            requireConsent: true,
            theme: ConsentTheme(
                primaryColor: .purple,
                cornerRadius: 16
            )
        ))
    }
}

3

Show the dialog & check consent

Swift
// Show in SwiftUI
Button("Privacy Settings") {
    showConsentDialog = true
}
.fullScreenCover(isPresented: $showConsentDialog) {
    ConsentDialogView {
        showConsentDialog = false
    }
}

// Check consent
let hasAnalytics = DuckCMP.hasConsent(categoryId: 2)
let status = DuckCMP.getConsentStatus()  // .unknown, .accepted, .rejected, .partial

Documentation

Configuration Reference

Every property you can configure, with types and defaults

`ConsentConfig`

Main configuration object passed to DuckCMP.initialize(). All properties have sensible defaults.

Property	Type	Default	Description
categories	List<ConsentCategory>	4 defaults	Consent categories shown to the user.
dialogTitle	String	"Privacy Settings"	Heading displayed at the top of the consent dialog.
dialogMessage	String	"We use cookies and similar…"	Body text explaining what consent means.
acceptAllLabel	String	"Accept All"	Text for the accept-all button.
rejectAllLabel	String	"Reject All"	Text for the reject-all button.
saveChoicesLabel	String	"Save Choices"	Text for saving individual toggle choices.
manageLabel	String	"Manage Preferences"	Text for expanding to show category toggles (Banner layout).
showCategoryToggles	Boolean	true	Whether to show per-category toggle switches.
requireConsent	Boolean	false	If true, dialog cannot be dismissed without choosing. Blocks back button and overlay tap.
buttons	List<ConsentButton>	[ACCEPT_ALL, REJECT_ALL, SAVE_CHOICES, MANAGE]	Which buttons to show and in what order. Omit to hide.
layout	ConsentLayout	POPUP	Presentation style: BANNER, POPUP, FULLSCREEN, BOTTOM_SHEET.
theme	ConsentTheme	Default theme	Visual customization: colors, corner radius, overlay.

`ConsentCategory`

Defines a single consent category shown to the user.

Property	Type	Description
id	Int	Unique identifier. Used to query consent with `hasConsent(id)`.
name	String	Display name shown in the dialog (e.g. "Analytics").
description	String	Explanation shown under the category name.
isRequired	Boolean	If true, toggle is always on and disabled. Default: false.

`ConsentTheme`

Visual customization for the consent dialog.

Property	Default	Description
primaryColor	0xFF1976D2	Buttons, toggles, active elements.
backgroundColor	0xFFFFFFFF	Dialog background color.
textColor	0xFF212121	Body text color.
titleColor	0xFF212121	Dialog heading color.
buttonTextColor	0xFFFFFFFF	Primary button label color.
secondaryButtonTextColor	0xFF1976D2	Outlined/secondary button text.
cornerRadius	12f	Corner radius for dialog and buttons (dp).
overlayColor	0x80000000	Background dimming overlay (ARGB).

`ConsentButton`

Controls which buttons appear and their visual order.

Value	Style	Behavior
ACCEPT_ALL	Primary filled	Grants consent for all categories. Saves and dismisses.
REJECT_ALL	Outlined	Rejects all optional categories (required stay on).
SAVE_CHOICES	Primary filled	Saves individual toggle selections.
MANAGE	Text link	Expands to show per-category toggles.

Order in the list = order on screen. Omit a button to hide it entirely.

`ConsentLayout`

Dialog presentation style.

Value	Description
BANNER	Compact bottom bar with accept/reject. "Manage" expands to show toggles.
POPUP	Centered modal dialog. The default. Balanced visibility.
FULLSCREEN	Full-screen overlay. Maximum attention. Ideal with `requireConsent`.
BOTTOM_SHEET	Draggable bottom sheet (~85% height). Scrollable with pinned buttons.

`ConsentStatus`

Returned by getConsentStatus().

Value	Meaning
UNKNOWN	No consent stored yet. User hasn't interacted with the dialog.
ACCEPTED	All categories consented (including optional ones).
REJECTED	All optional categories rejected. Only required ones active.
PARTIAL	Some optional categories accepted, some rejected.

Custom Categories Example

Kotlin
DuckCMP.initialize(this, ConsentConfig(
    categories = listOf(
        ConsentCategory(
            id = 1,
            name = "Essential",
            description = "Required for core functionality.",
            isRequired = true
        ),
        ConsentCategory(
            id = 2,
            name = "Performance",
            description = "Crash reports and performance metrics."
        ),
        ConsentCategory(
            id = 3,
            name = "Targeting",
            description = "Personalized ad delivery."
        ),
        ConsentCategory(
            id = 4,
            name = "Social",
            description = "Share content to social networks."
        )
    )
))

Swift
DuckCMP.initialize(config: ConsentConfig(
    categories: [
        ConsentCategory(
            id: 1,
            name: "Essential",
            description: "Required for core functionality.",
            isRequired: true
        ),
        ConsentCategory(
            id: 2,
            name: "Performance",
            description: "Crash reports and performance metrics."
        ),
        ConsentCategory(
            id: 3,
            name: "Targeting",
            description: "Personalized ad delivery."
        ),
        ConsentCategory(
            id: 4,
            name: "Social",
            description: "Share content to social networks."
        )
    ]
))

Theme Example

Kotlin
DuckCMP.initialize(this, ConsentConfig(
    theme = ConsentTheme(
        primaryColor = 0xFF6200EE,       // Purple accent
        backgroundColor = 0xFFFFFFFF,    // White background
        textColor = 0xFF333333,          // Dark gray body text
        titleColor = 0xFF111111,         // Near-black headings
        buttonTextColor = 0xFFFFFFFF,    // White button labels
        secondaryButtonTextColor = 0xFF6200EE,
        cornerRadius = 16f,             // Rounded corners
        overlayColor = 0x99000000       // 60% black overlay
    )
))

Button Ordering

The order of buttons in the list determines their order on screen. Omit any button to hide it.

Kotlin
// Show save first, then accept, then reject. Hide "Manage".
ConsentConfig(
    buttons = listOf(
        ConsentButton.SAVE_CHOICES,
        ConsentButton.ACCEPT_ALL,
        ConsentButton.REJECT_ALL
    )
)

// Only show accept and reject
ConsentConfig(
    buttons = listOf(
        ConsentButton.ACCEPT_ALL,
        ConsentButton.REJECT_ALL
    )
)

API Reference

Public API

Identical interface on both platforms. All methods are static on DuckCMP.

Method	Returns	Description
initialize(context, config?)	void	Initialize the SDK. Call once at app start. Config is optional (uses defaults).
showConsentDialog(activity)	void	Present the consent dialog using the configured layout.
getConsentStatus()	ConsentStatus	Returns UNKNOWN, ACCEPTED, REJECTED, or PARTIAL.
getConsentResult()	ConsentResult?	Full consent snapshot with per-category details and timestamp.
hasConsent(categoryId)	Boolean	Check if a specific category has been granted consent.
shouldShowDialog()	Boolean	Returns true if no consent has been stored yet.
saveConsent(result)	void	Programmatically save a consent result. Triggers callbacks and WebView sync.
reset()	void	Clear all stored consent. Triggers `onConsentRevoked` callback.
getConfig()	ConsentConfig	Returns the current configuration.
updateConfig(config)	void	Update configuration at runtime (e.g., switch layout or theme).
addCallback(callback)	void	Register a listener for consent changes.
removeCallback(callback)	void	Unregister a listener.
attachToWebView(webView)	void	Inject the `__duckcmp` JS bridge into a WebView.
detachFromWebView(webView)	void	Remove the JS bridge from a WebView.

ConsentCallback

Interface/protocol with three methods. Implement only what you need.

Method	Called When
onConsentGiven(result)	User accepts, rejects, or saves individual choices. Receives the full `ConsentResult`.
onConsentRevoked()	`reset()` is called. All stored consent is cleared.
onDialogDismissed()	The consent dialog is closed (by user choice or programmatically).

Storage

How consent is persisted

Platform-native storage. Queryable from anywhere in your app.

Android

SharedPreferences named "duckcmp"

iOS

UserDefaults.standard

Storage Keys
duckcmp_result         // Full JSON consent result
duckcmp_timestamp      // Unix timestamp of last consent action
duckcmp_status         // "ACCEPTED" | "REJECTED" | "PARTIAL" | "UNKNOWN"
duckcmp_category_{id}  // Per-category boolean (e.g. duckcmp_category_2 = true)

Per-category keys let you check consent from anywhere without initializing the SDK — useful in background services, content providers, or broadcast receivers.

Open Source Consent
Management for Apps

Everything you need

4 Layout Options

Full Theming

Custom Categories

WebView Bridge

Require Consent

Two Native SDKs

Default Categories

Layout Options

Banner

Popup

Fullscreen

Bottom Sheet

Up and running in minutes

Add the dependency

Initialize & configure

Show the dialog & check consent

Add the package

Initialize & configure

Show the dialog & check consent

Configuration Reference

`ConsentConfig`

`ConsentCategory`

`ConsentTheme`

`ConsentButton`

`ConsentLayout`

`ConsentStatus`

Custom Categories Example

Theme Example

Button Ordering

Public API

ConsentCallback

The `__duckcmp` Interface

1. Attach to WebView (native side)

2. Use from JavaScript

How it works

How consent is persisted

Android

iOS

Open Source ConsentManagement for Apps

Everything you need

4 Layout Options

Full Theming

Custom Categories

WebView Bridge

Require Consent

Two Native SDKs

Default Categories

Layout Options

Banner

Popup

Fullscreen

Bottom Sheet

Up and running in minutes

Add the dependency

Initialize & configure

Show the dialog & check consent

Add the package

Initialize & configure

Show the dialog & check consent

Configuration Reference

ConsentConfig

ConsentCategory

ConsentTheme

ConsentButton

ConsentLayout

ConsentStatus

Custom Categories Example

Theme Example

Button Ordering

Public API

ConsentCallback

The __duckcmp Interface

1. Attach to WebView (native side)

2. Use from JavaScript

How it works

How consent is persisted

Android

iOS

Open Source Consent
Management for Apps

`ConsentConfig`

`ConsentCategory`

`ConsentTheme`

`ConsentButton`

`ConsentLayout`

`ConsentStatus`

The `__duckcmp` Interface