diff --git a/src/main/java/com/formance/formance_sdk/utils/custom_helpers/PaymentsAccountId.java b/src/main/java/com/formance/formance_sdk/utils/custom_helpers/PaymentsAccountId.java
new file mode 100644
index 00000000..9d5274dd
--- /dev/null
+++ b/src/main/java/com/formance/formance_sdk/utils/custom_helpers/PaymentsAccountId.java
@@ -0,0 +1,34 @@
+// Package custom helpers provides utilities to easy usage of Formance API.
+// This file is NOT auto-generated and can be freely modified.
+package com.formance.formance_sdk.utils.custom_helpers;
+
+import java.util.Base64;
+import java.nio.charset.StandardCharsets;
+
+public class PaymentsAccountId {
+    /**
+         * Creates an account ID string
+         * @param connectorId The ID of the connector
+         * @param reference   The identifier of the account from the connector's provider.
+         * @return The identifier for Formance payments account.
+         * @throws IllegalArgumentException if connectorId or reference is null/blank, or if connectorId is invalid.
+         * 
+    */
+    public static String Build(String connectorId, String reference) {
+        if (connectorId == null || connectorId.isBlank()) {
+            throw new IllegalArgumentException("connectorId must not be null or blank");
+        }
+        if (reference == null || reference.isBlank()) {
+            throw new IllegalArgumentException("reference must not be null or blank");
+        }
+
+        String connectorIdJson = new String(Base64.getDecoder().decode(connectorId), StandardCharsets.UTF_8);
+        String json = String.format("{\"ConnectorID\":%s,\"Reference\":\"%s\"}", connectorIdJson, reference.replace("\\", "\\\\").replace("\"", "\\\""));
+
+        try {
+            return Base64.getEncoder().withoutPadding().encodeToString(json.getBytes(StandardCharsets.UTF_8));
+        } catch (Exception e) {
+            throw new IllegalArgumentException("Failed to build account ID. Please check if the connectorId is valid.", e);
+        }
+    }
+}