diff --git a/core-security/src/main/java/org/opendevstack/apiservice/core/security/util/Base64Operations.java b/core-security/src/main/java/org/opendevstack/apiservice/core/security/util/Base64Operations.java
new file mode 100644
index 0000000..41e4a62
--- /dev/null
+++ b/core-security/src/main/java/org/opendevstack/apiservice/core/security/util/Base64Operations.java
@@ -0,0 +1,40 @@
+package org.opendevstack.apiservice.core.security.util;
+
+import java.util.Base64;
+
+public class Base64Operations {
+
+    private Base64Operations() {}
+
+    /**
+     * Encodes a string value using Base64 encoding.
+     *
+     * @param value the string value to encode
+     * @return the Base64 encoded string, or null if input is null
+     */
+    public static String encode(String value) {
+        if (value == null) {
+            return null;
+        }
+        return Base64.getEncoder().encodeToString(value.getBytes());
+    }
+
+    /**
+     * Decodes a Base64 encoded string value.
+     *
+     * @param encodedValue the Base64 encoded string to decode
+     * @return the decoded string, or null if input is null
+     * @throws IllegalArgumentException if the input is not valid Base64
+     */
+    public static String decode(String encodedValue) {
+        if (encodedValue == null) {
+            return null;
+        }
+        try {
+            byte[] decodedBytes = Base64.getDecoder().decode(encodedValue);
+            return new String(decodedBytes);
+        } catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException("Invalid Base64 encoded value: " + encodedValue, e);
+        }
+    }
+}
diff --git a/core-security/src/test/java/org/opendevstack/apiservice/core/security/util/Base64OperationsTest.java b/core-security/src/test/java/org/opendevstack/apiservice/core/security/util/Base64OperationsTest.java
new file mode 100644
index 0000000..5b08a04
--- /dev/null
+++ b/core-security/src/test/java/org/opendevstack/apiservice/core/security/util/Base64OperationsTest.java
@@ -0,0 +1,51 @@
+package org.opendevstack.apiservice.core.security.util;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class Base64OperationsTest {
+
+    @Test
+    void tectEncodeWhenNullInputReturnNull() {
+        String testString = null;
+
+        String encodedString = Base64Operations.encode(testString);
+
+        assertEquals(null, encodedString);
+    }
+
+    @Test
+    void tectEncodeWhenCorrectInputReturnEncodedResult() {
+        String testString = "test;string";
+
+        String encodedString = Base64Operations.encode(testString);
+
+        assertEquals("dGVzdDtzdHJpbmc=", encodedString);
+    }
+
+    @Test
+    void testDecodeWhenNullInputReturnNull() {
+        String testString = null;
+
+        String dencodedString = Base64Operations.decode(testString);
+
+        assertEquals(null, dencodedString);
+    }
+
+    @Test
+    void testDecodeWhenCorrectInputReturnDecodedResult() {
+        String testString = "dGVzdDtzdHJpbmc=";
+
+        String dencodedString = Base64Operations.decode(testString);
+
+        assertEquals("test;string", dencodedString);
+    }
+
+    @Test
+    void testDecodeWhenBadInputThrowException() {
+        String testString = "NOT AN ENCODED STRING";
+
+        assertThrows(IllegalArgumentException.class, () -> Base64Operations.decode(testString));
+    }
+}
\ No newline at end of file
diff --git a/external-service-marketplace/src/main/java/org/opendevstack/apiservice/externalservice/marketplace/client/MarketplaceApiClient.java b/external-service-marketplace/src/main/java/org/opendevstack/apiservice/externalservice/marketplace/client/MarketplaceApiClient.java
index 6205674..53d2f04 100644
--- a/external-service-marketplace/src/main/java/org/opendevstack/apiservice/externalservice/marketplace/client/MarketplaceApiClient.java
+++ b/external-service-marketplace/src/main/java/org/opendevstack/apiservice/externalservice/marketplace/client/MarketplaceApiClient.java
@@ -4,6 +4,7 @@
 import lombok.Getter;
 import lombok.extern.slf4j.Slf4j;
 import org.openapitools.jackson.nullable.JsonNullableModule;
+import org.opendevstack.apiservice.core.security.util.Base64Operations;
 import org.opendevstack.apiservice.externalservice.marketplace.config.MarketplaceInstanceConfig;
 import org.opendevstack.apiservice.externalservice.marketplace.openapi.ApiClient;
 import org.opendevstack.apiservice.externalservice.marketplace.openapi.auth.HttpBearerAuth;
@@ -39,7 +40,7 @@ public MarketplaceApiClient(String instanceName, MarketplaceInstanceConfig confi
 
         if (config.getUsername() != null && config.getPassword() != null) {
             this.apiClient.setUsername(config.getUsername());
-            this.apiClient.setPassword(config.getPassword());
+            this.apiClient.setPassword(Base64Operations.decode(config.getPassword()));
             log.info("MarketplaceApiClient for instance '{}' uses basic authentication", instanceName);
         }