diff --git a/iguana/exchanges/LP_commands.c b/iguana/exchanges/LP_commands.c
index 5a76fc503..157294820 100644
--- a/iguana/exchanges/LP_commands.c
+++ b/iguana/exchanges/LP_commands.c
@@ -104,7 +104,8 @@ enable(coin)\n\
 disable(coin)\n\
 inventory(coin)\n\
 bestfit(rel, relvolume)\n\
-buy(base, rel, price, relvolume, timeout=10, duration=3600)\n\
+buy(base, rel, price, relvolume, timeout=10, duration=3600, nonce)\n\
+sell(base, rel, price, basevolume, timeout=10, duration=3600, nonce)\n\
 swapstatus()\n\
 swapstatus(requestid, quoteid)\n\
 public API:\n \
@@ -233,14 +234,14 @@ dividends(coin, height, <args>)\n\
             {
                 if ( price > SMALLVAL )
                 {
-                    return(LP_autobuy(ctx,myipaddr,pubsock,base,rel,price,jdouble(argjson,"relvolume"),jint(argjson,"timeout"),jint(argjson,"duration"),jstr(argjson,"gui")));
+                    return(LP_autobuy(ctx,myipaddr,pubsock,base,rel,price,jdouble(argjson,"relvolume"),jint(argjson,"timeout"),jint(argjson,"duration"),jstr(argjson,"gui"),juint(argjson,"nonce")));
                 } else return(clonestr("{\"error\":\"no price set\"}"));
             }
             else if ( strcmp(method,"sell") == 0 )
             {
                 if ( price > SMALLVAL )
                 {
-                    return(LP_autobuy(ctx,myipaddr,pubsock,rel,base,1./price,jdouble(argjson,"basevolume"),jint(argjson,"timeout"),jint(argjson,"duration"),jstr(argjson,"gui")));
+                    return(LP_autobuy(ctx,myipaddr,pubsock,rel,base,1./price,jdouble(argjson,"basevolume"),jint(argjson,"timeout"),jint(argjson,"duration"),jstr(argjson,"gui"),juint(argjson,"nonce")));
                 } else return(clonestr("{\"error\":\"no price set\"}"));
             }
         }
diff --git a/iguana/exchanges/LP_nativeDEX.c b/iguana/exchanges/LP_nativeDEX.c
index 205b98f67..75e020d50 100644
--- a/iguana/exchanges/LP_nativeDEX.c
+++ b/iguana/exchanges/LP_nativeDEX.c
@@ -47,6 +47,7 @@ char *default_LPnodes[] = { "5.9.253.195", "5.9.253.196", "5.9.253.197", "5.9.25
 
 //uint32_t LP_deadman_switch;
 uint16_t LP_fixed_pairport,LP_publicport;
+uint32_t LP_lastnonce;
 int32_t LP_mybussock = -1;
 int32_t LP_mypubsock = -1;
 int32_t LP_mypullsock = -1;
diff --git a/iguana/exchanges/LP_ordermatch.c b/iguana/exchanges/LP_ordermatch.c
index 5ff3cf7e4..20d927bff 100644
--- a/iguana/exchanges/LP_ordermatch.c
+++ b/iguana/exchanges/LP_ordermatch.c
@@ -1024,10 +1024,16 @@ struct LP_utxoinfo *LP_buyutxo(double *ordermatchpricep,int64_t *bestsatoshisp,i
     return(bestutxo);
 }
 
-char *LP_autobuy(void *ctx,char *myipaddr,int32_t mypubsock,char *base,char *rel,double maxprice,double relvolume,int32_t timeout,int32_t duration,char *gui)
+char *LP_autobuy(void *ctx,char *myipaddr,int32_t mypubsock,char *base,char *rel,double maxprice,double relvolume,int32_t timeout,int32_t duration,char *gui,uint32_t nonce)
 {
-    uint64_t desttxfee,txfee; int32_t i,maxiters,numpubs = 0; int64_t bestsatoshis=0,destsatoshis,bestdestsatoshis=0; struct LP_utxoinfo *autxo,*bestutxo = 0; double qprice,ordermatchprice=0.; struct LP_quoteinfo Q; bits256 pubkeys[100];
-    printf("LP_autobuy %s/%s price %.8f vol %.8f\n",base,rel,maxprice,relvolume);
+    uint64_t desttxfee,txfee; uint32_t lastnonce; int32_t i,maxiters,numpubs = 0; int64_t bestsatoshis=0,destsatoshis,bestdestsatoshis=0; struct LP_utxoinfo *autxo,*bestutxo = 0; double qprice,ordermatchprice=0.; struct LP_quoteinfo Q; bits256 pubkeys[100];
+    printf("LP_autobuy %s/%s price %.8f vol %.8f nonce %u\n",base,rel,maxprice,relvolume,nonce);
+    if ( (lastnonce= LP_lastnonce) != 0 && nonce <= lastnonce )
+    {
+        printf("nonce.%u not bigger than lastnonce.%u\n",nonce,lastnonce);
+        return(clonestr("{\"error\":\"invalid nonce\"}"));
+    }
+    LP_lastnonce = nonce;
     if ( duration <= 0 )
         duration = LP_ORDERBOOK_DURATION;
     if ( timeout <= 0 )
diff --git a/iguana/exchanges/LP_portfolio.c b/iguana/exchanges/LP_portfolio.c
index 80ce16c7b..75e8fd330 100644
--- a/iguana/exchanges/LP_portfolio.c
+++ b/iguana/exchanges/LP_portfolio.c
@@ -441,7 +441,7 @@ int32_t LP_portfolio_trade(void *ctx,uint32_t *requestidp,uint32_t *quoteidp,str
                 break;
             if ( LP_utxo_bestfit(sell->symbol,SATOSHIDEN * relvolume) != 0 )
             {
-                if ( (retstr2= LP_autobuy(ctx,"127.0.0.1",-1,buy->symbol,sell->symbol,maxprice,relvolume,60,24*3600,gui)) != 0 )
+                if ( (retstr2= LP_autobuy(ctx,"127.0.0.1",-1,buy->symbol,sell->symbol,maxprice,relvolume,60,24*3600,gui,LP_lastnonce+1)) != 0 )
                 {
                     if ( (retjson2= cJSON_Parse(retstr2)) != 0 )
                     {