Swift / iOS

CloudMock does not require a custom Swift SDK. Instead, configure the AWS SDK for Swift (or raw URLSession calls) to point at your CloudMock gateway running on localhost. This works for iOS simulators, macOS apps, and server-side Swift.

AWS SDK for Swift configuration

Install the AWS SDK for Swift

Add the AWS SDK to your Package.swift:

dependencies: [
    .package(url: "https://github.com/awslabs/aws-sdk-swift.git", from: "1.0.0"),
],
targets: [
    .target(
        name: "MyApp",
        dependencies: [
            .product(name: "AWSS3", package: "aws-sdk-swift"),
            .product(name: "AWSDynamoDB", package: "aws-sdk-swift"),
        ]
    ),
]

Configure the endpoint

Point each service client at CloudMock by setting a custom endpoint:

import AWSS3
import AWSDynamoDB
import AWSClientRuntime
import SmithyIdentity

// CloudMock endpoint -- use your Mac's IP when running on iOS Simulator
let cloudmockEndpoint = "http://localhost:4566"

// For iOS Simulator, use the host machine's IP instead of localhost:
// let cloudmockEndpoint = "http://192.168.1.100:4566"

let credentials = AWSCredentialIdentity(
    accessKey: "test",
    secret: "test"
)

let credentialResolver = try StaticAWSCredentialIdentityResolver(credentials)

// S3
let s3Config = try await S3Client.S3ClientConfiguration(
    awsCredentialIdentityResolver: credentialResolver,
    region: "us-east-1",
    endpoint: cloudmockEndpoint
)
s3Config.forcePathStyle = true
let s3 = S3Client(config: s3Config)

// Create a bucket
try await s3.createBucket(input: CreateBucketInput(bucket: "my-bucket"))

// DynamoDB
let ddbConfig = try await DynamoDBClient.DynamoDBClientConfiguration(
    awsCredentialIdentityResolver: credentialResolver,
    region: "us-east-1",
    endpoint: cloudmockEndpoint
)
let dynamodb = DynamoDBClient(config: ddbConfig)

Conditional endpoint (debug vs. release)

func makeS3Client() async throws -> S3Client {
    #if DEBUG
    let config = try await S3Client.S3ClientConfiguration(
        awsCredentialIdentityResolver: try StaticAWSCredentialIdentityResolver(
            AWSCredentialIdentity(accessKey: "test", secret: "test")
        ),
        region: "us-east-1",
        endpoint: "http://localhost:4566"
    )
    config.forcePathStyle = true
    return S3Client(config: config)
    #else
    let config = try await S3Client.S3ClientConfiguration(region: "us-east-1")
    return S3Client(config: config)
    #endif
}

URLSession configuration

For direct HTTP calls to CloudMock (without the AWS SDK), use a standard URLSession:

let endpoint = URL(string: "http://localhost:4566")!

// List S3 buckets
var request = URLRequest(url: endpoint)
request.httpMethod = "GET"
request.setValue("us-east-1", forHTTPHeaderField: "X-Amz-Region")

let (data, response) = try await URLSession.shared.data(for: request)

iOS Simulator networking

When running on the iOS Simulator, localhost refers to the simulator’s loopback interface, which is the same as the host Mac. CloudMock running on the Mac is accessible at http://localhost:4566 from the simulator without any special configuration.

For physical iOS devices on the same network, use the Mac’s local IP address (e.g., http://192.168.1.100:4566).

App Transport Security

During development, you may need to allow insecure HTTP connections in your Info.plist:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsLocalNetworking</key>
    <true/>
</dict>

The NSAllowsLocalNetworking key permits HTTP connections to localhost and .local domains without requiring HTTPS.

Supported services

All 98 AWS services emulated by CloudMock are accessible from Swift. The most commonly used from iOS/macOS apps:

• S3 — File uploads, downloads, presigned URLs
• DynamoDB — NoSQL database operations
• Cognito — User authentication and sign-up flows
• SNS — Push notification registration
• SQS — Message queue operations
• Lambda — Invoke serverless functions
• API Gateway — REST API calls (though you may call your API server directly)

Common issues

S3 path style

Always set forcePathStyle = true on the S3 client configuration. CloudMock does not support virtual-hosted style S3 URLs.

Simulator vs. device

The iOS Simulator shares the host Mac’s network stack, so localhost works. Physical devices require the Mac’s IP address on the local network.