Kotlin Multiplatform image loading with Coil 3 in 2026

TL;DR:

Coil 3 offers efficient image loading for Kotlin Multiplatform.
Configuring caching improves app performance significantly.
This guide covers everything from setup to advanced image transformations.

How does Coil 3 work with Compose Multiplatform?

Coil 3 seamlessly integrates with Compose Multiplatform, allowing you to load images efficiently across platforms. This library uses Kotlin Coroutines to perform asynchronous image loading, making it perfect for modern mobile applications. You can utilize Coil for shared code, which enhances your development workflow and reduces redundancy.

How do you set up Coil 3 for Kotlin Multiplatform?

Setting up Coil 3 for Kotlin Multiplatform involves a few straightforward steps. First, you need to add the necessary dependencies to your project. Here’s how to configure your build.gradle.kts file:

kotlin
kotlin {  
    sourceSets {  
        val commonMain by getting {  
            dependencies {  
                implementation("io.coil-kt:coil:3.x")  
                implementation("io.coil-kt:coil-compose:3.x")  
            }  
        }  
    }  
}

Make sure to replace 3.x with the latest version of Coil. Once this is done, you can start using Coil in your shared codebase.

What are the steps to display an image using Coil 3?

Displaying an image with Coil 3 is simple and efficient. Follow these steps to show an image in your Compose UI:

Add dependencies as mentioned above.
Create an ImageLoader instance for loading images.
Use AsyncImage to display images in your Composable function.

Here is a code snippet demonstrating these steps:

kotlin
val imageLoader = ImageLoader(context)  
AsyncImage(  
    model = "https://example.com/image.jpg",  
    contentDescription = "Sample Image",  
    imageLoader = imageLoader  
)

How do you configure caching for Coil 3?

Coil 3 offers both memory and disk caching, improving the performance of your applications. You can configure these caches during the ImageLoader setup. Here’s how:

kotlin
val imageLoader = ImageLoader.Builder(context)  
    .memoryCacheEnabled(true)  
    .diskCacheEnabled(true)  
    .build()

This configuration allows Coil to cache images in memory and on disk, reducing load times and improving your app's responsiveness.

How can you handle placeholders and error states in Coil 3?

Coil 3 allows you to handle loading states gracefully by using placeholders and error images. You can specify these parameters in the AsyncImage composable as follows:

kotlin
AsyncImage(  
    model = "https://example.com/image.jpg",  
    contentDescription = "Sample Image",  
    placeholder = painterResource(id = R.drawable.placeholder),  
    error = painterResource(id = R.drawable.error),  
    imageLoader = imageLoader  
)

This code will display a placeholder image while the main image loads and an error image if the load fails.

What image transformations can you apply with Coil 3?

Coil 3 supports various image transformations, such as rounding corners and applying blur effects. You can apply these transformations directly in the AsyncImage call. Here’s an example of how to apply rounded corners:

kotlin
AsyncImage(  
    model = "https://example.com/image.jpg",  
    contentDescription = "Sample Image",  
    modifier = Modifier.clip(RoundedCornerShape(8.dp)),  
    imageLoader = imageLoader  
)

For a blur effect, use the following code:

kotlin
val imageLoader = ImageLoader.Builder(context)  
    .components {  
        add(BlurTransformation(context))  
    }  
    .build()

How do you preload images in Coil 3?

Preloading images can enhance user experience by ensuring that images are available before they are displayed. You can easily preload an image using the ImageLoader like this:

kotlin
imageLoader.enqueue(  
    ImageRequest.Builder(context)  
        .data("https://example.com/image.jpg")  
        .build()  
)

This approach allows images to be cached before they are needed, resulting in a smoother user experience.

How do you use platform-specific cache directories?

Coil 3 allows you to specify platform-specific cache directories, which is useful for managing storage effectively. You can customize the cache directory by configuring the ImageLoader:

kotlin
val imageLoader = ImageLoader.Builder(context)  
    .diskCacheSize(250 * 1024 * 1024) // 250 MB  
    .build()

This setup ensures that your application efficiently manages disk space while caching images.

How does Coil 3 compare to other image loading libraries?

Here’s a comparison between Coil 3, Kamel, and manual image loading for Kotlin Multiplatform:

Feature	Coil 3	Kamel	Manual Loading
Caching	Yes (disk & memory)	Yes (disk)	No
Image transformations	Yes	Limited	Manual required
Integration with Compose	Excellent	Good	Complicated
Performance	High	Medium	Variable
Asynchronous loading	Yes	Yes	No

Conclusion

Coil 3 provides a powerful and efficient way to handle image loading in Kotlin Multiplatform applications. With its straightforward setup, robust caching features, and easy integration with Compose Multiplatform, it's an excellent choice for developers. KMPShip includes Coil image loading pre-configured in all tiers, making it even easier to get started. Start implementing Coil 3 in your projects today for a seamless image loading experience!

Frequently Asked Questions

What is Coil 3?

Coil 3 is an image loading library for Android and Kotlin Multiplatform that simplifies the loading and caching of images. It utilizes Kotlin Coroutines for asynchronous operations, making it efficient for modern apps.

How do I implement image caching with Coil 3?

You can implement image caching by configuring the ImageLoader with memory and disk cache enabled. This allows Coil to store images for quick retrieval, enhancing performance.

What are the advantages of using Coil over other image loaders?

Coil offers several advantages, including built-in image transformations, easy integration with Compose, and excellent performance due to its coroutine-based approach.

Can I use Coil with iOS in Kotlin Multiplatform?

Yes, Coil supports iOS as part of Kotlin Multiplatform, allowing you to use the same image loading functionality across both Android and iOS platforms.

Is Coil 3 suitable for production apps?

Absolutely. Coil 3 is designed for production use, with features like efficient caching, image transformations, and robust error handling, making it ideal for mobile applications.