AsyncImage in WWDC26: Native HTTP Caching, Request-Level Control, and Custom Sessions

With the 2027 OS releases (iOS 27, macOS 27, watchOS 27, tvOS 27, visionOS 27), SwiftUI introduces one of the most meaningful upgrades yet to AsyncImage: automatic HTTP caching by default, along with new APIs for fine-grained control when needed.

The goal is simple: less boilerplate, better performance, and optional control when you actually need it.

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🚀 Automatic HTTP Caching (No Code Changes Required)

Starting on iOS 27+, AsyncImage(url:) automatically benefits from standard HTTP caching behavior.

This means:

• Server cache headers are fully respected (Cache-Control, ETag, etc.)

• Previously loaded images can be served directly from cache

• No opt-in API is required

• No configuration changes are needed

Basic usage (now cache-enabled by default)

AsyncImage(url: imageURL)

What changed?

• Before: every request could hit the network again depending on implementation details

• Now: responses are cached automatically when running on OS 27+

📌 Important notes:

• This is runtime behavior, not a compile-time SDK feature

• It applies automatically on supported OS versions even for older deployments

• No API exists to “enable caching” because it is always on

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🔧 New: Request-Based Control with URLRequest

A new initializer gives you full control over the request:

AsyncImage(request: URLRequest(url: imageURL, cachePolicy: .returnCacheDataElseLoad))

This allows you to configure:

• Cache policy per image

• Revalidation behavior

• Forced reload strategies

• Any additional URLRequest customization

Available cache policies

• .useProtocolCachePolicy

• .returnCacheDataElseLoad

• .returnCacheDataDontLoad

• .reloadIgnoringLocalCacheData

• .reloadRevalidatingCacheData

Example with placeholder

AsyncImage(
    request: URLRequest(
        url: imageURL,
        cachePolicy: .returnCacheDataElseLoad
    )
) { image in
    image
        .resizable()
        .scaledToFit()
} placeholder: {
    ProgressView()
}

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🌐 New: asyncImageURLSession Modifier

Another major addition is the ability to inject a custom URLSession:

.asyncImageURLSession(customSession)

This gives you control over:

• Memory cache size

• Disk cache size

• Global caching strategy

• Shared caching across multiple views

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🧠 Real-world Example: Optimized Image Gallery

ScrollView(.horizontal) {
    LazyHStack(spacing: 20) {
        ForEach(imageURLs, id: \.self) { url in
            AsyncImage(
                request: URLRequest(url: url, cachePolicy: .returnCacheDataElseLoad),
                scale: 2
            ) { image in
                image
                    .resizable()
                    .scaledToFill()
            } placeholder: {
                ProgressView()
            }
            .frame(width: 280, height: 180)
            .clipShape(.rect(cornerRadius: 20))
        }
    }
}
.asyncImageURLSession(.imageCache)

And a custom session setup:

extension URLSession {
    static let imageCache: URLSession = {
        let cache = URLCache(
            memoryCapacity: 20 * 1024 * 1024,
            diskCapacity: 100 * 1024 * 1024
        )

        let config = URLSessionConfiguration.default
        config.urlCache = cache
        config.requestCachePolicy = .returnCacheDataElseLoad

        return URLSession(configuration: config)
    }()
}

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⚡ What Problem Does This Solve?

Before iOS 27:

• Developers had to manage image caching manually

• Many apps implemented custom loaders

• Cache behavior was inconsistent across implementations

Now:

• AsyncImage is cache-aware by default

• Customization is optional, not required

• Most apps can remove custom image loading layers entirely

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📊 Feature Summary

FeatureAvailabilityTypeAutomatic HTTP cachingiOS 27+Runtime behaviorAsyncImage(request:)iOS 27+APIasyncImageURLSession(_:)iOS 27+API

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🧩 Conclusion

The new AsyncImage moves SwiftUI toward a production-ready image loading system out of the box.

In practice:

• 80% of apps → AsyncImage(url:) is now enough

• Advanced apps → URLRequest + custom URLSession provide full control

It’s a clear step toward reducing infrastructure code and making image loading a first-class, cache-aware SwiftUI feature.