diff --git a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/MQTTUtils.java b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/MQTTUtils.java
index 6a078b4c0..e88935c56 100644
--- a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/MQTTUtils.java
+++ b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/MQTTUtils.java
@@ -588,25 +588,6 @@ public class MQTTUtils extends Thread
         addToSendQueue( context, tap );
     }
 
-    public static void ackMessage( Context context, String topic, int gameID,
-                                   String senderDevID, byte[] payload )
-    {
-        String sum = Utils.getMD5SumFor( payload );
-        JSONObject params = new JSONObject();
-        try {
-            params.put( "topic", topic );
-            params.put( "gid", gameID );
-            params.put( "sum", sum );
-
-            HttpURLConnection conn
-                = NetUtils.makeHttpMQTTConn( context, "ack" );
-            String resStr = NetUtils.runConn( conn, params, true );
-            Log.d( TAG, "runConn(ack) => %s", resStr );
-        } catch ( JSONException je ) {
-            Log.e( TAG, "ackMessage() ex: %s", je );
-        }
-    }
-
     // MqttCallbackExtended
     @Override
     public void connectComplete( boolean reconnect, String serverURI )
diff --git a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/NetUtils.java b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/NetUtils.java
index ab04b0c2a..a5b1bb8a0 100644
--- a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/NetUtils.java
+++ b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/NetUtils.java
@@ -145,6 +145,22 @@ public class NetUtils {
         context.startActivity( intent );
     }
 
+    public static void sendViaWeb( final Context context, final String api,
+                                   final String jsonParams )
+    {
+        Log.d( TAG, "sendViaWeb(api: %s, params: %s)", api, jsonParams );
+
+        new Thread( new Runnable() {
+                @Override
+                public void run() {
+                    HttpURLConnection conn = makeHttpMQTTConn( context, api );
+                    boolean directJson = true;
+                    String result = runConn( conn, jsonParams, directJson );
+                    Log.d( TAG, "sendViaWeb(api: %s): got result '%s'", api, result );
+                }
+            } ).start();
+    }
+
     public static HttpURLConnection makeHttpMQTTConn( Context context,
                                                       String proc )
     {
@@ -159,8 +175,8 @@ public class NetUtils {
         return makeHttpConn( context, url, proc );
     }
 
-    private static HttpURLConnection makeHttpConn( Context context,
-                                                    String path, String proc )
+    private static HttpURLConnection makeHttpConn( Context context, String path,
+                                                   String proc )
     {
         HttpURLConnection result = null;
         try {
diff --git a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/DUtilCtxt.java b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/DUtilCtxt.java
index 407fbad92..2696866f1 100644
--- a/xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/DUtilCtxt.java
+++ b/xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/DUtilCtxt.java
@@ -38,6 +38,7 @@ import org.eehouse.android.xw4.GamesListDelegate;
 import org.eehouse.android.xw4.Log;
 import org.eehouse.android.xw4.MQTTUtils;
 import org.eehouse.android.xw4.NetLaunchInfo;
+import org.eehouse.android.xw4.NetUtils;
 import org.eehouse.android.xw4.R;
 import org.eehouse.android.xw4.Utils;
 import org.eehouse.android.xw4.XWApp;
@@ -333,6 +334,11 @@ public class DUtilCtxt {
         DupeModeTimer.timerChanged( m_context, gameID, newVal );
     }
 
+    public void sendViaWeb( String api, String jsonParams )
+    {
+        NetUtils.sendViaWeb( m_context, api, jsonParams );
+    }
+
     public void onInviteReceived( NetLaunchInfo nli )
     {
         // Log.d( TAG, "onInviteReceived(%s)", nli );
@@ -358,9 +364,4 @@ public class DUtilCtxt {
     {
         MQTTUtils.handleCtrlReceived( m_context, msg );
     }
-
-    public void ackMQTTMsg( String topic, int gameID, String senderID, byte[] msg )
-    {
-        MQTTUtils.ackMessage( m_context, topic, gameID, senderID, msg );
-    }
 }
diff --git a/xwords4/android/jni/Android.mk b/xwords4/android/jni/Android.mk
index 665960778..717fed148 100644
--- a/xwords4/android/jni/Android.mk
+++ b/xwords4/android/jni/Android.mk
@@ -95,7 +95,9 @@ COMMON_SRC_FILES +=        \
 	$(COMMON_PATH)/dutil.c  	\
 	$(COMMON_PATH)/device.c  	\
 	$(COMMON_PATH)/knownplyr.c  \
-	$(COMMON_PATH)/dllist.c  \
+	$(COMMON_PATH)/dllist.c     \
+	$(COMMON_PATH)/cJSON.c      \
+	$(COMMON_PATH)/cJSON_Utils.c\
 
 LOCAL_CFLAGS+=$(LOCAL_C_INCLUDES) $(LOCAL_DEFINES) -Wall -std=c99
 LOCAL_SRC_FILES := $(linux_SRC_FILES) $(LOCAL_SRC_FILES) $(COMMON_SRC_FILES)
diff --git a/xwords4/android/jni/utilwrapper.c b/xwords4/android/jni/utilwrapper.c
index fc5a4de79..824844b89 100644
--- a/xwords4/android/jni/utilwrapper.c
+++ b/xwords4/android/jni/utilwrapper.c
@@ -970,22 +970,16 @@ and_dutil_onGameGoneReceived( XW_DUtilCtxt* duc, XWEnv xwe, XP_U32 gameID,
 }
 
 static void
-and_dutil_ackMQTTMsg( XW_DUtilCtxt* duc, XWEnv xwe, const XP_UCHAR* topic,
-                      XP_U32 gameID, const MQTTDevID* senderID, const XP_U8* msg,
-                      XP_U16 len )
+and_dutil_sendViaWeb( XW_DUtilCtxt* duc, XWEnv xwe, const XP_UCHAR* api,
+                      const cJSON* params )
 {
-    DUTIL_CBK_HEADER( "ackMQTTMsg", "(Ljava/lang/String;ILjava/lang/String;[B)V" );
-
-    XP_UCHAR tmp[32];
-    formatMQTTDevID( senderID, tmp, VSIZE(tmp) );
-    jstring jTopic = (*env)->NewStringUTF( env, topic );
-    jstring jdevid = (*env)->NewStringUTF( env, tmp );
-    jbyteArray jmsg = makeByteArray( env, len, (const jbyte*)msg );
-
-    (*env)->CallVoidMethod( env, dutil->jdutil, mid, jTopic, gameID,
-                            jdevid, jmsg );
-
-    deleteLocalRefs( env, jdevid, jmsg, DELETE_NO_REF );
+    DUTIL_CBK_HEADER( "sendViaWeb", "(Ljava/lang/String;Ljava/lang/String;)V" );
+    char* pstr = cJSON_PrintUnformatted( params );
+    jstring jParams = (*env)->NewStringUTF( env, pstr );
+    jstring jApi = (*env)->NewStringUTF( env, api );
+    (*env)->CallVoidMethod( env, dutil->jdutil, mid, jApi, jParams );
+    deleteLocalRefs( env, jApi, jParams, DELETE_NO_REF );
+    free( pstr );
     DUTIL_CBK_TAIL();
 }
 
@@ -1145,7 +1139,7 @@ makeDUtil( MPFORMAL JNIEnv* env,
     SET_DPROC(onCtrlReceived);
 
     SET_DPROC(onGameGoneReceived);
-    SET_DPROC(ackMQTTMsg);
+    SET_DPROC(sendViaWeb);
 
 #undef SET_DPROC
 
diff --git a/xwords4/common/device.c b/xwords4/common/device.c
index 4bf11fdc8..2fc8275ca 100644
--- a/xwords4/common/device.c
+++ b/xwords4/common/device.c
@@ -507,9 +507,7 @@ ackMQTTMsg( XW_DUtilCtxt* dutil, XWEnv xwe, const XP_UCHAR* topic,
     dutil_md5sum( dutil, xwe, buf, len, &sb );
     cJSON_AddStringToObject( params, "sum", sb.buf );
 
-    XP_UCHAR gid16[16];
-    XP_SNPRINTF( gid16, VSIZE(gid16), "%08X", gameID );
-    cJSON_AddStringToObject( params, "gid16", gid16 );
+    cJSON_AddNumberToObject( params, "gid", gameID );
 
     dutil_sendViaWeb( dutil, xwe, "ack", params );
     cJSON_Delete( params );
diff --git a/xwords4/common/dutil.h b/xwords4/common/dutil.h
index fced5ac21..4f4125f2f 100644
--- a/xwords4/common/dutil.h
+++ b/xwords4/common/dutil.h
@@ -102,10 +102,6 @@ typedef struct _DUtilVtable {
     void (*m_dutil_onCtrlReceived)( XW_DUtilCtxt* duc, XWEnv xwe, const XP_U8* buf, XP_U16 len );
     void (*m_dutil_onGameGoneReceived)( XW_DUtilCtxt* duc, XWEnv xwe, XP_U32 gameID,
                                        const CommsAddrRec* from );
-
-    void (*m_dutil_ackMQTTMsg)( XW_DUtilCtxt* duc, XWEnv xwe, const XP_UCHAR* topic,
-                                XP_U32 gameID, const MQTTDevID* senderID,
-                                const XP_U8* msg, XP_U16 len );
     void (*m_dutil_sendViaWeb)( XW_DUtilCtxt* duc, XWEnv xwe, const XP_UCHAR* api,
                                 const cJSON* params );
 } DUtilVtable;
@@ -185,9 +181,6 @@ void dutil_super_init( MPFORMAL XW_DUtilCtxt* dutil );
     (duc)->vtable.m_dutil_onCtrlReceived((duc),(xwe),(buf),(len))
 #define dutil_onGameGoneReceived(duc, xwe, gameID, from)         \
     (duc)->vtable.m_dutil_onGameGoneReceived((duc),(xwe),(gameID),(from))
-#define dutil_ackMQTTMsg( duc, xwe, topic, gameID, senderID, msg, len ) \
-    (duc)->vtable.m_dutil_ackMQTTMsg( (duc), (xwe), (topic), (gameID),  \
-                                      (senderID), (msg), (len) )
 #define dutil_sendViaWeb( duc, xwe, api, params )                       \
     (duc)->vtable.m_dutil_sendViaWeb((duc), (xwe), (api), (params))
 #endif
diff --git a/xwords4/linux/lindutil.c b/xwords4/linux/lindutil.c
index 5f2e9cab3..df005d6e7 100644
--- a/xwords4/linux/lindutil.c
+++ b/xwords4/linux/lindutil.c
@@ -202,59 +202,59 @@ linux_dutil_onGameGoneReceived( XW_DUtilCtxt* duc, XWEnv XP_UNUSED(xwe),
     }
 }
 
-typedef struct _AckData {
-    XW_DUtilCtxt* duc;
-    XP_U8* msg;
-    XP_U16 len;
-    gchar* topic;
-    XP_U32 gameID;
-} AckData;
+/* typedef struct _AckData { */
+/*     XW_DUtilCtxt* duc; */
+/*     XP_U8* msg; */
+/*     XP_U16 len; */
+/*     gchar* topic; */
+/*     XP_U32 gameID; */
+/* } AckData; */
 
-static void
-sendViaCurl( LinDUtilCtxt* lduc, AckData* adp )
-{
-    LaunchParams* params = (LaunchParams*)lduc->super.closure;
+/* static void */
+/* sendViaCurl( LinDUtilCtxt* lduc, AckData* adp ) */
+/* { */
+/*     LaunchParams* params = (LaunchParams*)lduc->super.closure; */
 
-    CURLcode res = curl_global_init(CURL_GLOBAL_DEFAULT);
-    XP_ASSERT(res == CURLE_OK);
-    CURL* curl = curl_easy_init();
+/*     CURLcode res = curl_global_init(CURL_GLOBAL_DEFAULT); */
+/*     XP_ASSERT(res == CURLE_OK); */
+/*     CURL* curl = curl_easy_init(); */
 
-    char url[128];
-    snprintf( url, sizeof(url), "https://%s/xw4/api/v1/ack",
-              params->connInfo.mqtt.hostName );
-    curl_easy_setopt( curl, CURLOPT_URL, url );
+/*     char url[128]; */
+/*     snprintf( url, sizeof(url), "https://%s/xw4/api/v1/ack", */
+/*               params->connInfo.mqtt.hostName ); */
+/*     curl_easy_setopt( curl, CURLOPT_URL, url ); */
 
-    gchar* sum = g_compute_checksum_for_data( G_CHECKSUM_MD5, adp->msg, adp->len );
-    gchar* json
-        = g_strdup_printf("{\"topic\": \"%s\", \"gid\": %u, \"sum\": \"%s\"}",
-                          adp->topic, adp->gameID, sum );
-    // XP_LOGFF( "json: %s", json );
-    g_free( sum );
-    curl_easy_setopt( curl, CURLOPT_POSTFIELDS, json );
-    curl_easy_setopt( curl, CURLOPT_POSTFIELDSIZE, -1L );
+/*     gchar* sum = g_compute_checksum_for_data( G_CHECKSUM_MD5, adp->msg, adp->len ); */
+/*     gchar* json */
+/*         = g_strdup_printf("{\"topic\": \"%s\", \"gid\": %u, \"sum\": \"%s\"}", */
+/*                           adp->topic, adp->gameID, sum ); */
+/*     // XP_LOGFF( "json: %s", json ); */
+/*     g_free( sum ); */
+/*     curl_easy_setopt( curl, CURLOPT_POSTFIELDS, json ); */
+/*     curl_easy_setopt( curl, CURLOPT_POSTFIELDSIZE, -1L ); */
 
-    struct curl_slist *headers = NULL;
-    headers = curl_slist_append(headers, "Expect:");
-    headers = curl_slist_append(headers, "Content-Type: application/json");
-    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
+/*     struct curl_slist *headers = NULL; */
+/*     headers = curl_slist_append(headers, "Expect:"); */
+/*     headers = curl_slist_append(headers, "Content-Type: application/json"); */
+/*     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); */
 
-    res = curl_easy_perform(curl);
-    XP_Bool success = res == CURLE_OK;
-    /* XP_LOGFF( "curl_easy_perform() => %d", res ); */
-    if ( ! success ) {
-        XP_LOGFF( "curl_easy_perform() failed: %s", curl_easy_strerror(res));
-    }
+/*     res = curl_easy_perform(curl); */
+/*     XP_Bool success = res == CURLE_OK; */
+/*     /\* XP_LOGFF( "curl_easy_perform() => %d", res ); *\/ */
+/*     if ( ! success ) { */
+/*         XP_LOGFF( "curl_easy_perform() failed: %s", curl_easy_strerror(res)); */
+/*     } */
 
-    curl_slist_free_all( headers );
-    curl_easy_cleanup( curl );
-    curl_global_cleanup();
-    g_free( json );
+/*     curl_slist_free_all( headers ); */
+/*     curl_easy_cleanup( curl ); */
+/*     curl_global_cleanup(); */
+/*     g_free( json ); */
 
-    /* g_idle_add( nuke_ack_data, ad ); */
-    g_free( adp->topic );
-    g_free( adp->msg );
-    g_free( adp );
-}
+/*     /\* g_idle_add( nuke_ack_data, ad ); *\/ */
+/*     g_free( adp->topic ); */
+/*     g_free( adp->msg ); */
+/*     g_free( adp ); */
+/* } */
 
 #ifdef ACK_IN_BACKGROUND
 static void*
@@ -284,32 +284,32 @@ sendAckThreadProc( void* arg )
 }
 #endif
 
-static void
-linux_dutil_ackMQTTMsg( XW_DUtilCtxt* duc, XWEnv XP_UNUSED(xwe),
-                        const XP_UCHAR* topic, XP_U32 gameID,
-                        const MQTTDevID* XP_UNUSED(senderID),
-                        const XP_U8* msg, XP_U16 len )
-{
-    AckData ad = {
-        .duc = duc,
-        .topic = g_strdup( topic ),
-        .gameID = gameID,
-        .len = len,
-        .msg = g_memdup2( msg, len ),
-    };
-    AckData* adp = g_memdup2( &ad, sizeof(ad) );
+/* static void */
+/* linux_dutil_ackMQTTMsg( XW_DUtilCtxt* duc, XWEnv XP_UNUSED(xwe), */
+/*                         const XP_UCHAR* topic, XP_U32 gameID, */
+/*                         const MQTTDevID* XP_UNUSED(senderID), */
+/*                         const XP_U8* msg, XP_U16 len ) */
+/* { */
+/*     AckData ad = { */
+/*         .duc = duc, */
+/*         .topic = g_strdup( topic ), */
+/*         .gameID = gameID, */
+/*         .len = len, */
+/*         .msg = g_memdup2( msg, len ), */
+/*     }; */
+/*     AckData* adp = g_memdup2( &ad, sizeof(ad) ); */
 
-    LinDUtilCtxt* lduc = (LinDUtilCtxt*)duc;
-#ifdef ACK_IN_BACKGROUND
-    pthread_mutex_lock( &lduc->ackMutex );
-    lduc->ackList = g_list_append( lduc->ackList, adp );
-    pthread_cond_signal( &lduc->ackCondVar );
-    pthread_mutex_unlock( &lduc->ackMutex );
-#else
-    sendViaCurl( lduc, adp );
-#endif
-    /* LOG_RETURN_VOID(); */
-}
+/*     LinDUtilCtxt* lduc = (LinDUtilCtxt*)duc; */
+/* #ifdef ACK_IN_BACKGROUND */
+/*     pthread_mutex_lock( &lduc->ackMutex ); */
+/*     lduc->ackList = g_list_append( lduc->ackList, adp ); */
+/*     pthread_cond_signal( &lduc->ackCondVar ); */
+/*     pthread_mutex_unlock( &lduc->ackMutex ); */
+/* #else */
+/*     sendViaCurl( lduc, adp ); */
+/* #endif */
+/*     /\* LOG_RETURN_VOID(); *\/ */
+/* } */
 
 static void
 linux_dutil_sendViaWeb( XW_DUtilCtxt* duc, XWEnv xwe, const XP_UCHAR* api,
@@ -371,7 +371,6 @@ linux_dutils_init( MPFORMAL VTableMgr* vtMgr, void* closure )
     SET_PROC(onMessageReceived);
     SET_PROC(onCtrlReceived);
     SET_PROC(onGameGoneReceived);
-    SET_PROC(ackMQTTMsg);
     SET_PROC(sendViaWeb);
 
 # undef SET_PROC