diff --git a/common/src/main/java/de/bluecolored/bluemap/common/web/http/HttpHeader.java b/common/src/main/java/de/bluecolored/bluemap/common/web/http/HttpHeader.java
index 8d95de7fb..8318b7467 100644
--- a/common/src/main/java/de/bluecolored/bluemap/common/web/http/HttpHeader.java
+++ b/common/src/main/java/de/bluecolored/bluemap/common/web/http/HttpHeader.java
@@ -80,13 +80,28 @@ public synchronized boolean contains(String value) {
         if (valuesLC == null) {
             valuesLC = new HashSet<>();
             for (String v : getValues()) {
-                valuesLC.add(v.toLowerCase(Locale.ROOT));
+                String[] parts = v.split(";");
+                if (hasZeroQuality(parts)) continue;
+                valuesLC.add(parts[0].trim().toLowerCase(Locale.ROOT));
             }
         }
 
         return valuesLC.contains(value);
     }
 
+    private static boolean hasZeroQuality(String[] parts) {
+        for (int i = 1; i < parts.length; i++) {
+            String param = parts[i].trim();
+            if (!param.regionMatches(true, 0, "q=", 0, 2)) continue;
+            try {
+                return Double.parseDouble(param.substring(2)) == 0;
+            } catch (NumberFormatException ignore) {
+                return false;
+            }
+        }
+        return false;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (o == null || getClass() != o.getClass()) return false;
diff --git a/common/src/test/java/de/bluecolored/bluemap/common/web/http/HttpHeaderTest.java b/common/src/test/java/de/bluecolored/bluemap/common/web/http/HttpHeaderTest.java
new file mode 100644
index 000000000..d3a7ef964
--- /dev/null
+++ b/common/src/test/java/de/bluecolored/bluemap/common/web/http/HttpHeaderTest.java
@@ -0,0 +1,73 @@
+/*
+ * This file is part of BlueMap, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) Blue (Lukas Rieger) <https://bluecolored.de>
+ * Copyright (c) contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package de.bluecolored.bluemap.common.web.http;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class HttpHeaderTest {
+
+    @Test
+    public void testContainsPlainValues() {
+        HttpHeader header = new HttpHeader("Accept-Encoding", "gzip, deflate, br");
+        assertTrue(header.contains("gzip"));
+        assertTrue(header.contains("br"));
+        assertFalse(header.contains("zstd"));
+    }
+
+    @Test
+    public void testContainsIgnoresParameters() {
+        HttpHeader header = new HttpHeader("Accept-Encoding", "gzip;q=1.0, deflate ; q=0.5, br;q=0.8");
+        assertTrue(header.contains("gzip"));
+        assertTrue(header.contains("deflate"));
+        assertTrue(header.contains("br"));
+    }
+
+    @Test
+    public void testContainsExcludesZeroQuality() {
+        HttpHeader header = new HttpHeader("Accept-Encoding", "gzip;q=0, zstd;Q=0.000, br;q=0.001, identity;q=abc");
+        assertFalse(header.contains("gzip"));
+        assertFalse(header.contains("zstd"));
+        assertTrue(header.contains("br"));
+        assertTrue(header.contains("identity"));
+    }
+
+    @Test
+    public void testContainsIsCaseInsensitive() {
+        HttpHeader header = new HttpHeader("Transfer-Encoding", "Chunked");
+        assertTrue(header.contains("chunked"));
+    }
+
+    @Test
+    public void testContainsAfterAdd() {
+        HttpHeader header = new HttpHeader("Accept-Encoding", "deflate");
+        assertFalse(header.contains("gzip"));
+        header.add("gzip;q=0.9");
+        assertTrue(header.contains("gzip"));
+    }
+
+}