diff --git a/runelite-client/src/main/java/net/runelite/client/RuneLite.java b/runelite-client/src/main/java/net/runelite/client/RuneLite.java
index 06a03e4a2d..b4e3300cc2 100644
--- a/runelite-client/src/main/java/net/runelite/client/RuneLite.java
+++ b/runelite-client/src/main/java/net/runelite/client/RuneLite.java
@@ -89,6 +89,7 @@ public class RuneLite
 	public static final File SCREENSHOT_DIR = new File(RUNELITE_DIR, "screenshots");
 	public static final File LOGS_DIR = new File(RUNELITE_DIR, "logs");
 	private static final RuneLiteSplashScreen splashScreen = new RuneLiteSplashScreen();
+	public static boolean allowPrivateServer = false;
 
 	@Getter
 	private static Injector injector;
@@ -181,6 +182,7 @@ public class RuneLite
 		parser.accepts("debug", "Show extra debugging output");
 		parser.accepts("no-splash", "Do not show the splash screen");
 		parser.accepts("local-injected", "Use local injected-client");
+		parser.accepts("private-server", "Use a custom codebase");
 
 		final ArgumentAcceptingOptionSpec<String> proxyInfo = parser
 			.accepts("proxy")
@@ -264,6 +266,11 @@ public class RuneLite
 			ClientLoader.useLocalInjected = true;
 		}
 
+		if (options.has("private-server"))
+		{
+			allowPrivateServer = true;
+		}
+
 		Thread.setDefaultUncaughtExceptionHandler((thread, throwable) ->
 		{
 			log.error("Uncaught exception:", throwable);
diff --git a/runelite-client/src/main/java/net/runelite/client/rs/RSAppletStub.java b/runelite-client/src/main/java/net/runelite/client/rs/RSAppletStub.java
index 71c1a5ae8e..8d5944cdf0 100644
--- a/runelite-client/src/main/java/net/runelite/client/rs/RSAppletStub.java
+++ b/runelite-client/src/main/java/net/runelite/client/rs/RSAppletStub.java
@@ -30,6 +30,7 @@ import java.applet.AppletStub;
 import java.net.MalformedURLException;
 import java.net.URL;
 import lombok.RequiredArgsConstructor;
+import net.runelite.client.RuneLite;
 import net.runelite.client.util.StringFileUtils;
 
 @RequiredArgsConstructor
@@ -54,7 +55,10 @@ class RSAppletStub implements AppletStub
 	{
 		try
 		{
+			if (RuneLite.allowPrivateServer)
 			return new URL(StringFileUtils.readStringFromFile("./codebase"));
+
+			return new URL(config.getCodeBase());
 		}
 		catch (MalformedURLException ex)
 		{