diff --git a/vtm-tests/test/org/oscim/tiling/source/UrlTileSourceTest.java b/vtm-tests/test/org/oscim/tiling/source/UrlTileSourceTest.java
index b52eb830..f9441420 100644
--- a/vtm-tests/test/org/oscim/tiling/source/UrlTileSourceTest.java
+++ b/vtm-tests/test/org/oscim/tiling/source/UrlTileSourceTest.java
@@ -1,9 +1,26 @@
+/*
+ * Copyright 2016 devemux86
+ *
+ * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
 package org.oscim.tiling.source;
 
 import static org.fest.assertions.api.Assertions.assertThat;
 
 import org.junit.Before;
 import org.junit.Test;
+import org.oscim.core.Tile;
 import org.oscim.tiling.ITileDataSource;
 
 public class UrlTileSourceTest {
@@ -14,6 +31,12 @@ public class UrlTileSourceTest {
 		tileSource = new TestTileSource("http://example.org/tiles/vtm", "/{Z}/{X}/{Z}.vtm");
 	}
 
+	@Test
+	public void setApiKey_shouldAppendApiKey() throws Exception {
+		tileSource.setApiKey("testkey");
+		assertThat(tileSource.getTileUrl(new Tile(0, 0, (byte) 0))).endsWith("?api_key=testkey");
+	}
+
 	@Test
 	public void shouldNotBeNull() throws Exception {
 		assertThat(tileSource).isNotNull();
diff --git a/vtm/src/org/oscim/tiling/source/UrlTileSource.java b/vtm/src/org/oscim/tiling/source/UrlTileSource.java
index ac1c0140..b35cb947 100644
--- a/vtm/src/org/oscim/tiling/source/UrlTileSource.java
+++ b/vtm/src/org/oscim/tiling/source/UrlTileSource.java
@@ -1,5 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
+ * Copyright 2016 devemux86
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
  *
@@ -31,6 +32,7 @@ public abstract class UrlTileSource extends TileSource {
 		protected String tilePath;
 		protected String url;
 		private HttpEngine.Factory engineFactory;
+		private String apiKey;
 
 		protected Builder() {
 
@@ -43,6 +45,11 @@ public abstract class UrlTileSource extends TileSource {
 			this.zoomMax = zoomMax;
 		}
 
+		public T apiKey(String apiKey) {
+			this.apiKey = apiKey;
+			return self();
+		}
+
 		public T tilePath(String tilePath) {
 			this.tilePath = tilePath;
 			return self();
@@ -67,13 +74,15 @@ public abstract class UrlTileSource extends TileSource {
 	private HttpEngine.Factory mHttpFactory;
 	private Map<String, String> mRequestHeaders = Collections.emptyMap();
 	private TileUrlFormatter mTileUrlFormatter = URL_FORMATTER;
+	private String mApiKey;
 
 	public interface TileUrlFormatter {
-		public String formatTilePath(UrlTileSource tileSource, Tile tile);
+		String formatTilePath(UrlTileSource tileSource, Tile tile);
 	}
 
 	protected UrlTileSource(Builder<?> builder) {
 		super(builder);
+		mApiKey = builder.apiKey;
 		mUrl = makeUrl(builder.url);
 		mTilePath = builder.tilePath.split("\\{|\\}");
 		mHttpFactory = builder.engineFactory;
@@ -97,7 +106,7 @@ public abstract class UrlTileSource extends TileSource {
 	}
 
 	private URL makeUrl(String urlString) {
-		URL url = null;
+		URL url;
 		try {
 			url = new URL(urlString);
 		} catch (MalformedURLException e) {
@@ -116,12 +125,20 @@ public abstract class UrlTileSource extends TileSource {
 
 	}
 
+	public void setApiKey(String apiKey) {
+		mApiKey = apiKey;
+	}
+
 	public URL getUrl() {
 		return mUrl;
 	}
 
 	public String getTileUrl(Tile tile) {
-		return mUrl + mTileUrlFormatter.formatTilePath(this, tile);
+		String tileUrl = mUrl + mTileUrlFormatter.formatTilePath(this, tile);
+		if (mApiKey != null) {
+			tileUrl += String.format("?api_key=%s", mApiKey);
+		}
+		return tileUrl;
 	}
 
 	public void setHttpEngine(HttpEngine.Factory httpFactory) {
@@ -140,9 +157,6 @@ public abstract class UrlTileSource extends TileSource {
 		return mTilePath;
 	}
 
-	/**
-	 * 
-	 */
 	public void setUrlFormatter(TileUrlFormatter formatter) {
 		mTileUrlFormatter = formatter;
 	}