diff --git a/backend/src/main/java/org/cryptomator/hub/VueHistoryModeFilter.java b/backend/src/main/java/org/cryptomator/hub/filters/VueHistoryModeFilter.java
similarity index 59%
rename from backend/src/main/java/org/cryptomator/hub/VueHistoryModeFilter.java
rename to backend/src/main/java/org/cryptomator/hub/filters/VueHistoryModeFilter.java
index ea5a0686..9fe7db16 100644
--- a/backend/src/main/java/org/cryptomator/hub/VueHistoryModeFilter.java
+++ b/backend/src/main/java/org/cryptomator/hub/filters/VueHistoryModeFilter.java
@@ -1,4 +1,4 @@
-package org.cryptomator.hub;
+package org.cryptomator.hub.filters;
 
 import org.eclipse.microprofile.config.inject.ConfigProperty;
 
@@ -11,7 +11,6 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
-import java.util.regex.Pattern;
 
 /**
  * A global http filter which redirects all 404-responses to the frontend app root. Necessary for using <a href="https://v3.router.vuejs.org/guide/essentials/history-mode.html#example-server-configurations">history mode in the vue router</a>
@@ -21,8 +20,6 @@
 @WebFilter(urlPatterns = "/*")
 public class VueHistoryModeFilter extends HttpFilter {
 
-	private static final Pattern FILE_NAME_PATTERN = Pattern.compile(".*[.][a-zA-Z\\d]+");
-
 	@ConfigProperty(name = "quarkus.resteasy.path")
 	String apiPathPrefix;
 
@@ -31,19 +28,14 @@ public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
 		HttpServletResponse response = (HttpServletResponse) res;
 		chain.doFilter(request, response);
 
-		if (response.getStatus() == 404) {
-			String path = request.getRequestURI().substring(
-					request.getContextPath().length()).replaceAll("[/]+$", ""); //delete all "/" at end of string
-			if (!path.startsWith(apiPathPrefix) && !FILE_NAME_PATTERN.matcher(path).matches()) { //TODO: possibly exclude even more prefixes (e.g. keycloak)
-				// We could not find the resource, i.e. it is not anything known to the server (i.e. it is not a REST
-				// endpoint or a servlet), and does not look like a file so try handling it in the front-end routes
-				// and reset the response status code to 200.
-				try {
-					response.setStatus(200);
-					request.getRequestDispatcher("/").forward(request, response);
-				} finally {
-					response.getOutputStream().close();
-				}
+		// exclude requests to the ReST API from filtering:
+		String contextRelativePath = request.getRequestURI().substring(request.getContextPath().length());
+		if (response.getStatus() == 404 && !contextRelativePath.startsWith(apiPathPrefix)) {
+			try {
+				response.setStatus(200);
+				request.getRequestDispatcher("/").forward(request, response);
+			} finally {
+				response.getOutputStream().close();
 			}
 		}
 	}
diff --git a/backend/src/test/java/org/cryptomator/hub/filters/VueHistoryModeFilterTest.java b/backend/src/test/java/org/cryptomator/hub/filters/VueHistoryModeFilterTest.java
new file mode 100644
index 00000000..18afeb89
--- /dev/null
+++ b/backend/src/test/java/org/cryptomator/hub/filters/VueHistoryModeFilterTest.java
@@ -0,0 +1,84 @@
+package org.cryptomator.hub.filters;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.mockito.Mockito;
+
+import javax.servlet.FilterChain;
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class VueHistoryModeFilterTest {
+
+	private HttpServletRequest req = Mockito.mock(HttpServletRequest.class);
+	private HttpServletResponse res = Mockito.mock(HttpServletResponse.class);
+	private FilterChain chain = Mockito.mock(FilterChain.class);
+
+	private VueHistoryModeFilter filter = new VueHistoryModeFilter();
+
+	@BeforeEach
+	public void setup() {
+		filter.apiPathPrefix = "/api";
+	}
+
+	@ParameterizedTest(name = "path = {0}")
+	@ValueSource(strings = {"/ctx/api", "/ctx/api/foo?k=v", "/ctx/api/foo/bar/", "/ctx/api/"})
+	@DisplayName("don't filter requests to /ctx/api/*")
+	public void testDoNotFilterApi(String reqUri) throws ServletException, IOException {
+		Mockito.doReturn(reqUri).when(req).getRequestURI();
+		Mockito.doReturn("/ctx").when(req).getContextPath();
+		Mockito.doReturn(404).when(res).getStatus();
+
+		filter.doFilter(req, res, chain);
+
+		Mockito.verify(chain).doFilter(req, res);
+		Mockito.verify(req).getRequestURI();
+		Mockito.verify(req).getContextPath();
+		Mockito.verify(res).getStatus();
+		Mockito.verifyNoMoreInteractions(res, req, chain);
+	}
+
+	@ParameterizedTest(name = "statuscode = {0}")
+	@ValueSource(ints = {200, 201, 301, 401, 403})
+	@DisplayName("don't filter non-404 responses")
+	public void testDoNotFilterNon404(int status) throws ServletException, IOException {
+		Mockito.doReturn("/ctx/foo").when(req).getRequestURI();
+		Mockito.doReturn("/ctx").when(req).getContextPath();
+		Mockito.doReturn(status).when(res).getStatus();
+
+		filter.doFilter(req, res, chain);
+
+		Mockito.verify(chain).doFilter(req, res);
+		Mockito.verify(req).getRequestURI();
+		Mockito.verify(req).getContextPath();
+		Mockito.verify(res).getStatus();
+		Mockito.verifyNoMoreInteractions(res, req, chain);
+	}
+
+	@ParameterizedTest(name = "path = {0}")
+	@ValueSource(strings = {"/ctx", "/ctx/foo?k=v", "/ctx/foo/bar/"})
+	@DisplayName("filter 404 response to non-api resources")
+	public void testDoFilterNonApi(String reqUri) throws ServletException, IOException {
+		var dispatcher = Mockito.mock(RequestDispatcher.class);
+		var out = Mockito.mock(ServletOutputStream.class);
+		Mockito.doReturn(reqUri).when(req).getRequestURI();
+		Mockito.doReturn("/ctx").when(req).getContextPath();
+		Mockito.doReturn(404).when(res).getStatus();
+		Mockito.doReturn(dispatcher).when(req).getRequestDispatcher("/");
+		Mockito.doReturn(out).when(res).getOutputStream();
+
+		filter.doFilter(req, res, chain);
+
+		Mockito.verify(res).setStatus(200);
+		Mockito.verify(req).getRequestDispatcher("/");
+		Mockito.verify(dispatcher).forward(req, res);
+		Mockito.verify(out).close();
+	}
+
+}
\ No newline at end of file