To include custom headers in your outgoing requests, add an `URLRequestInterceptor` to the `AWSAPIPlugin`. Also specify the name of one of the APIs configured in your **amplifyconfiguration.json** file.

```swift
struct CustomInterceptor: URLRequestInterceptor {
    func intercept(_ request: URLRequest) throws -> URLRequest {
        var request = request
        request.setValue("headerValue", forHTTPHeaderField: "headerKey")
        return request
    }
}
let apiPlugin = try AWSAPIPlugin()
try Amplify.addPlugin(apiPlugin)
try Amplify.configure()
try apiPlugin.add(interceptor: CustomInterceptor(), for: "yourApiName")
```