diff --git a/api/src/main/java/io/kafbat/ui/emitter/MessageFilters.java b/api/src/main/java/io/kafbat/ui/emitter/MessageFilters.java
index 86a42aab1..402b5a43e 100644
--- a/api/src/main/java/io/kafbat/ui/emitter/MessageFilters.java
+++ b/api/src/main/java/io/kafbat/ui/emitter/MessageFilters.java
@@ -18,12 +18,12 @@
 import dev.cel.common.types.StructType;
 import dev.cel.compiler.CelCompiler;
 import dev.cel.compiler.CelCompilerFactory;
+import dev.cel.extensions.CelExtensions;
 import dev.cel.parser.CelStandardMacro;
 import dev.cel.runtime.CelEvaluationException;
 import dev.cel.runtime.CelRuntime;
 import dev.cel.runtime.CelRuntimeFactory;
 import io.kafbat.ui.exception.CelException;
-import io.kafbat.ui.model.MessageFilterTypeDTO;
 import io.kafbat.ui.model.TopicMessageDTO;
 import java.util.HashMap;
 import java.util.Map;
@@ -42,8 +42,7 @@ public class MessageFilters {
   private static final String CEL_RECORD_TYPE_NAME = TopicMessageDTO.class.getSimpleName();
 
   private static final CelCompiler CEL_COMPILER = createCompiler();
-  private static final CelRuntime CEL_RUNTIME = CelRuntimeFactory.standardCelRuntimeBuilder()
-      .build();
+  private static final CelRuntime CEL_RUNTIME = createRuntime();
 
   private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
 
@@ -143,6 +142,7 @@ private static CelCompiler createCompiler() {
     return CelCompilerFactory.standardCelCompilerBuilder()
         .setOptions(CelOptions.DEFAULT)
         .setStandardMacros(CelStandardMacro.STANDARD_MACROS)
+        .addLibraries(CelExtensions.strings(), CelExtensions.encoders())
         .addVar(CEL_RECORD_VAR_NAME, recordType)
         .setResultType(SimpleType.BOOL)
         .setTypeProvider(new CelTypeProvider() {
@@ -159,6 +159,12 @@ public Optional<CelType> findType(String typeName) {
         .build();
   }
 
+  private static CelRuntime createRuntime() {
+    return CelRuntimeFactory.standardCelRuntimeBuilder()
+        .addLibraries(CelExtensions.strings(), CelExtensions.encoders())
+        .build();
+  }
+
   @Nullable
   private static Object parseToJsonOrReturnAsIs(@Nullable String str) {
     if (str == null) {
diff --git a/api/src/test/java/io/kafbat/ui/emitter/MessageFiltersTest.java b/api/src/test/java/io/kafbat/ui/emitter/MessageFiltersTest.java
index 7cdcf00f6..cae8629eb 100644
--- a/api/src/test/java/io/kafbat/ui/emitter/MessageFiltersTest.java
+++ b/api/src/test/java/io/kafbat/ui/emitter/MessageFiltersTest.java
@@ -10,10 +10,11 @@
 import io.kafbat.ui.exception.CelException;
 import io.kafbat.ui.model.TopicMessageDTO;
 import java.time.OffsetDateTime;
-import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
+import java.util.Base64;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 import java.util.function.Predicate;
 import org.apache.commons.lang3.RandomStringUtils;
 import org.junit.jupiter.api.Nested;
@@ -100,7 +101,7 @@ void canCheckTimestampMs() {
       var ts = OffsetDateTime.now();
       var f = celScriptFilter("record.timestampMs == " + ts.toInstant().toEpochMilli());
       assertTrue(f.test(msg().timestamp(ts)));
-      assertFalse(f.test(msg().timestamp(ts.plus(1L, ChronoUnit.SECONDS))));
+      assertFalse(f.test(msg().timestamp(ts.plusSeconds(1L))));
     }
 
     @Test
@@ -177,6 +178,7 @@ void filterSpeedIsAtLeast5kPerSec() {
         toFilter.add(msg().content(jsonContent).key(randString));
       }
       // first iteration for warmup
+      // noinspection ResultOfMethodCallIgnored
       toFilter.stream().filter(f).count();
 
       long before = System.currentTimeMillis();
@@ -188,10 +190,15 @@ void filterSpeedIsAtLeast5kPerSec() {
     }
   }
 
+  @Test
+  void testBase64DecodingWorks() {
+    var uuid = UUID.randomUUID().toString();
+    var msg = "test." + Base64.getEncoder().encodeToString(uuid.getBytes());
+    var f = celScriptFilter("string(base64.decode(record.value.split('.')[1])).contains('" + uuid + "')");
+    assertTrue(f.test(msg().content(msg)));
+  }
+
   private TopicMessageDTO msg() {
-    return new TopicMessageDTO()
-        .timestamp(OffsetDateTime.now())
-        .offset(-1L)
-        .partition(1);
+    return new TopicMessageDTO(1, -1L, OffsetDateTime.now());
   }
 }