Migrating from Glide to Coil in Android with Kotlin

Image loading has always been one of those quiet challenges in Android development — the kind you only appreciate when it suddenly breaks or slows everything down. For years, Glide has been the go-to solution: powerful, versatile, and proven.

But the Android ecosystem has changed. As Kotlin and coroutines became the foundation of modern app development, many teams started to look for a library that feels more native to this new world. That’s where Coil (Coroutine Image Loader) comes in — a lightweight, Kotlin-first alternative designed for the modern Android stack.

If your app has been running Glide for years and you’re now considering a move to Coil, this guide will walk you through the process and help you migrate with confidence.

Why Developers Are Moving from Glide to Coil

Before jumping into refactoring, it’s worth understanding what you gain from switching — and why Coil has quietly become the preferred choice for new projects.

1. Kotlin-first and Coroutine-friendly

Coil is written entirely in Kotlin and designed around suspend functions and coroutines. It integrates smoothly with ViewModel, LiveData, and Flow, which makes it feel like a natural part of the Android architecture rather than an external dependency.

2. Smaller and Faster

Coil’s dependency footprint is roughly 60–70% smaller than Glide’s. It also avoids heavy reflection and initialization overhead, which translates into faster app startup and less memory churn.

3. Ready for Compose

If you’re building with Jetpack Compose, Coil is already one step ahead. You can load images with just one line:

AsyncImage(
    model = imageUrl,
    contentDescription = null
)

No adapters, no view bindings — just clean, declarative UI.

4. Cleaner Customization

With Coil, configuration is declarative and concise. You can easily define transformations, caching, and request behavior directly in Kotlin DSL form — no verbose builders or annotations required.

Updating Your Dependencies

First, remove Glide from your build.gradle:

// implementation("com.github.bumptech.glide:glide:4.x.x")
// kapt("com.github.bumptech.glide:compiler:4.x.x")

Then, add Coil:

implementation("io.coil-kt:coil:2.7.0")
implementation("io.coil-kt:coil-gif:2.7.0")
implementation("io.coil-kt:coil-svg:2.7.0")

If your project uses Jetpack Compose:

implementation("io.coil-kt:coil-compose:2.7.0")

That’s all you need — no annotation processing or generated API classes.

From Glide to Coil: The Basics

Here’s a quick side-by-side look.

With Glide:

Glide.with(context)
    .load(url)
    .placeholder(R.drawable.placeholder)
    .error(R.drawable.error)
    .centerCrop()
    .into(imageView)

With Coil:

imageView.load(url) {
    placeholder(R.drawable.placeholder)
    error(R.drawable.error)
    crossfade(true)
    transformations(CircleCropTransformation())
}

You’ll notice that Coil reads more like natural Kotlin code — concise, scoped, and expressive. No with(context) or explicit targets needed.

Migrating Common Glide Patterns

1. Image Transformations

Glide:

Glide.with(context)
    .load(url)
    .transform(CenterCrop(), RoundedCorners(16))
    .into(imageView)

Coil:

imageView.load(url) {
    transformations(CenterCropTransformation(), RoundedCornersTransformation(16f))
}

Coil’s transformation API uses plain Kotlin functions, so you avoid boilerplate and custom factories.

2. Handling Success and Errors

Glide:

Glide.with(context)
    .load(url)
    .listener(object : RequestListener<Drawable> {
        override fun onLoadFailed(
            e: GlideException?, model: Any?, target: Target<Drawable>?, isFirstResource: Boolean
        ): Boolean {
            Log.e("ImageLoad", "Failed: $e")
            return false
        }
        override fun onResourceReady(
            resource: Drawable?, model: Any?, target: Target<Drawable>?, dataSource: DataSource?, isFirstResource: Boolean
        ): Boolean {
            Log.d("ImageLoad", "Success!")
            return false
        }
    })
    .into(imageView)

Coil:

imageView.load(url) {
    listener(
        onSuccess = { _, _ -> Log.d("ImageLoad", "Success!") },
        onError = { _, throwable -> Log.e("ImageLoad", "Failed: $throwable") }
    )
}

The lambda-based syntax in Coil is simpler and fits seamlessly into structured Kotlin code.

3. Preloading and Caching

Glide:

Glide.with(context).load(url).preload()

Coil:

imageLoader.enqueue(
    ImageRequest.Builder(context)
        .data(url)
        .build()
)

You can also define your own global ImageLoader:

val imageLoader = ImageLoader.Builder(context)
    .crossfade(true)
    .memoryCachePolicy(CachePolicy.ENABLED)
    .build()

Inject this via Koin or Hilt to share it across modules.

Displaying GIFs with Coil

If your app uses animated GIFs, Coil supports them out of the box — just make sure you’ve added the GIF dependency:

implementation("io.coil-kt:coil-gif:2.7.0")

Then, load your GIFs exactly like static images:

imageView.load("https://example.com/animation.gif") {
    placeholder(R.drawable.placeholder)
    error(R.drawable.error)
}

That’s it — no special setup or additional API calls required. Coil automatically detects the GIF format and plays it natively.

If you’re using Compose, it works just as smoothly:

AsyncImage(
    model = "https://example.com/animation.gif",
    contentDescription = null
)

For large or continuously looping GIFs, you can also limit decoding or enable hardware acceleration through the ImageLoader configuration.

Migrating GlideApp and Custom Modules

If you’ve been using @GlideModule and GlideApp, Coil offers a simpler approach with manual configuration:

object CoilConfig {
    fun provideImageLoader(context: Context): ImageLoader =
        ImageLoader.Builder(context)
            .crossfade(true)
            .allowHardware(false)
            .bitmapPoolingEnabled(true)
            .build()
}

You can then load images like this:

val imageLoader = CoilConfig.provideImageLoader(context)
imageView.load(url, imageLoader)

A Step-by-Step Migration Strategy

Migrating large projects can be tricky, but it doesn’t have to be painful. A gradual approach works best:

1. Add Coil alongside Glide to start.
2. Migrate one module or feature at a time.
3. Compare results for caching, memory usage, and UI consistency.
4. Once all Glide usages are replaced, remove its dependencies entirely.
5. Run regression tests to ensure no behavior changes slipped through.
6. This phased migration ensures stability while modernizing your stack.

Performance Insights

In most real-world apps, Coil performs on par with or better than Glide — especially during cold starts. Its coroutine-based lifecycle awareness prevents unnecessary work when views are detached, and memory management is notably efficient.

That said, Glide might still have the upper hand for heavy custom transformations or advanced model loaders. But for most use cases, Coil’s simpler and more modern design wins out.

Conclusion

Migrating from Glide to Coil isn’t just a technical refactor — it’s a strategic move toward a cleaner, more maintainable Kotlin codebase. Coil’s coroutine support, Compose integration, and lightweight architecture make it a natural fit for modern Android apps.

If your team is already working with coroutines, Flow, or Jetpack libraries, you’ll find Coil integrates effortlessly with your existing patterns. Even if your project is still XML-based, its simplicity and speed improvements will make the change worthwhile.

Start small, validate results, and expand gradually. Once the transition is complete, you’ll have a faster, cleaner, and more future-proof image loading layer.

For full documentation, advanced configuration details, and official migration guides, please refer to Coil’s documentation: 👉 https://coil-kt.github.io/coil/