diff --git a/src/main/java/com/currencycloud/client/CurrencyCloudClient.java b/src/main/java/com/currencycloud/client/CurrencyCloudClient.java
index 10b6eae4..aad6b327 100644
--- a/src/main/java/com/currencycloud/client/CurrencyCloudClient.java
+++ b/src/main/java/com/currencycloud/client/CurrencyCloudClient.java
@@ -20,6 +20,9 @@
 
 import javax.annotation.Nullable;
 import java.math.BigDecimal;
+import java.net.MalformedURLException;
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.*;
 import java.util.regex.Pattern;
 
@@ -119,7 +122,18 @@ public CurrencyCloudClient(Environment environment, String loginId, String apiKe
         this(environment.url, loginId, apiKey, HttpClientConfiguration.builder().build());
     }
 
-    CurrencyCloudClient(String url, String loginId, String apiKey, HttpClientConfiguration httpClientConfiguration) {
+    public CurrencyCloudClient(String url, String loginId, String apiKey) {
+        this(url, loginId, apiKey, HttpClientConfiguration.builder().build());
+    }
+
+    public CurrencyCloudClient(String url, String loginId, String apiKey, HttpClientConfiguration httpClientConfiguration) {
+        String wellFormedUrl;
+        try {
+            wellFormedUrl = new URI(url).toURL().toString();
+        } catch (URISyntaxException | MalformedURLException e) {
+            throw new IllegalArgumentException(e);
+        }
+
         this.loginId = loginId;
         this.apiKey = apiKey;
         ClientConfig config = new ClientConfig();
@@ -144,7 +158,7 @@ public void configureObjectMapper(ObjectMapper objectMapper) {
         config.setHttpReadTimeout(httpClientConfiguration.getHttpReadTimeout());
 
         api = RestProxyFactory.createProxy(
-                CurrencyCloud.class, url, config,
+                CurrencyCloud.class, wellFormedUrl, config,
                 new AutoAuthenticator(this), new ExceptionTransformer(), new Reauthenticator(this)
         );
     }
diff --git a/src/test/java/com/currencycloud/client/CurrencyCloudClientSessionTest.java b/src/test/java/com/currencycloud/client/CurrencyCloudClientSessionTest.java
index 9b395039..38b5f077 100644
--- a/src/test/java/com/currencycloud/client/CurrencyCloudClientSessionTest.java
+++ b/src/test/java/com/currencycloud/client/CurrencyCloudClientSessionTest.java
@@ -4,39 +4,45 @@
 import org.junit.Test;
 
 import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertThrows;
 
 public class CurrencyCloudClientSessionTest {
 
     @Test
-    public void testRaisesAnErrorIfTheEnvironmentIsNotSet() throws Exception {
-        try {
-            CurrencyCloudClient client = new CurrencyCloudClient((CurrencyCloudClient.Environment) null, null, null);
-            client.authenticate();
-            throw new AssertionError("Should have failed.");
-        } catch (NullPointerException ignored) { }
+    public void testRaisesAnErrorIfTheEnvironmentIsNotSet() {
+        assertThrows(NullPointerException.class, () -> new CurrencyCloudClient((CurrencyCloudClient.Environment) null, null, null));
     }
 
     @Test
-    public void testRaisesAnErrorIfTheLoginIdIsNotSet() throws Exception {
+    public void testRaisesAnErrorIfTheLoginIdIsNotSet() {
         CurrencyCloudClient client = new CurrencyCloudClient(CurrencyCloudClient.Environment.demo, null, null);
-        try {
-            client.authenticate();
-            throw new AssertionError("Should have failed.");
-        } catch (IllegalArgumentException e) {
-            assertThat(e.getMessage(), containsString("apiKey must be set"));
-        }
+        Exception exception = assertThrows(IllegalArgumentException.class, client::authenticate);
+        assertThat(exception.getMessage(), containsString("apiKey must be set"));
     }
 
     @Test
-    public void testRaisesAnErrorIfTheApiKeyIsNotSet() throws Exception {
+    public void testRaisesAnErrorIfTheApiKeyIsNotSet() {
         CurrencyCloudClient client = new CurrencyCloudClient(CurrencyCloudClient.Environment.demo, "development@currencycloud.com", null);
-        try {
-            client.authenticate();
-            throw new AssertionError("Should have failed.");
-        } catch (IllegalArgumentException e) {
-            assertThat(e.getMessage(), containsString("apiKey"));
-            assertThat(e.getMessage(), containsString("must be set"));
-        }
+        Exception exception = assertThrows(IllegalArgumentException.class, client::authenticate);
+        assertThat(exception.getMessage(), containsString("apiKey must be set"));
+    }
+
+    @Test
+    public void testRaisesAnErrorIfTheUrlNoAbsolute() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> new CurrencyCloudClient("example.com", "development@currencycloud.com", "key"));
+        assertThat(exception.getMessage(), equalTo("URI is not absolute"));
+    }
+
+    @Test
+    public void testRaisesAnErrorIfTheUrlIncorrect() {
+        Exception exception = assertThrows(IllegalArgumentException.class, () -> new CurrencyCloudClient("example com", "development@currencycloud.com", "key"));
+        assertThat(exception.getMessage(), containsString("Illegal character in path at index 7: example com"));
+    }
+
+    @Test(expected = Test.None.class)
+    public void testValidUrlAndPortAccepted() {
+        new CurrencyCloudClient("http://localhost:8080", "development@currencycloud.com", "key");
     }
 }