How can I debug my retrofit API call?

Use HttpLoggingInterceptor along with Retrofit.

If this helps, add this inside your build.gradle –

//Retrofit and OkHttp for Networking
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
//Logging Network Calls
implementation 'com.squareup.okhttp3:logging-interceptor:4.9.1'

Inside your APIClient class add this –

public class ApiClient {
    private static Retrofit retrofit = null;

    public static Retrofit getClient(){

        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .build();


        if(retrofit==null){
            retrofit = new Retrofit.Builder()
                    .baseUrl(BuildConfig.baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(client)
                    .build();
        }
        return retrofit;
    }
}

Kotlin Code

val interceptor : HttpLoggingInterceptor = HttpLoggingInterceptor().apply {
            level = HttpLoggingInterceptor.Level.BODY
        }

val client : OkHttpClient = OkHttpClient.Builder().apply {
            addInterceptor(interceptor)
        }.build()


fun getService(): Service {
        return Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(LiveDataCallAdapterFactory())
                .client(client)
                .build()
                .create(Service::class.java)
    }

And you will be able to log the Retrofit Network calls that you make.

Let me know if you need more information.