diff --git a/PrebidMobile/PrebidMobile-core/src/main/java/org/prebid/mobile/ExternalUserId.java b/PrebidMobile/PrebidMobile-core/src/main/java/org/prebid/mobile/ExternalUserId.java
index f91eabd88..fa355ec81 100644
--- a/PrebidMobile/PrebidMobile-core/src/main/java/org/prebid/mobile/ExternalUserId.java
+++ b/PrebidMobile/PrebidMobile-core/src/main/java/org/prebid/mobile/ExternalUserId.java
@@ -99,7 +99,7 @@ public JSONObject getJson() {
         try {
             JSONObject uidObject = new JSONObject();
             uidObject.putOpt("id", getIdentifier());
-            uidObject.putOpt("adtype", getAtype());
+            uidObject.putOpt("atype", getAtype());
             if (getExt() != null) {
                 uidObject.putOpt("ext", new JSONObject(getExt()));
             }