diff --git a/src/gmc_con.erl b/src/gmc_con.erl
index 41e5fb9..3e593ce 100644
--- a/src/gmc_con.erl
+++ b/src/gmc_con.erl
@@ -15,7 +15,7 @@
          open_wallet/2, close_wallet/0, new_wallet/3, import_wallet/3, drop_wallet/2,
          password/2,
          refresh/0,
-         nonce/1, spend/2, chain/1, grids/1, sign_mess/1,
+         nonce/1, spend/2, chain/1, grids/1, sign_mess/1, sign_tx/1,
          make_key/6, recover_key/1, mnemonic/1, rename_key/2, drop_key/1,
          add_node/1, set_sole_node/1]).
 -export([encrypt/2, decrypt/2]).
@@ -154,6 +154,13 @@ sign_mess(Request) ->
     gen_server:cast(?MODULE, {sign_mess, Request}).
 
 
+-spec sign_tx(Request) -> ok
+    when Request :: map().
+
+sign_tx(Request) ->
+    gen_server:cast(?MODULE, {sign_tx, Request}).
+
+
 -spec make_key(Type, Size, Name, Seed, Encoding, Transform) -> ok
     when Type      :: {eddsa, ed25519},
          Size      :: 256,
@@ -345,6 +352,9 @@ handle_cast({grids, String}, State) ->
 handle_cast({sign_mess, Request}, State) ->
     ok = do_sign_mess(Request, State),
     {noreply, State};
+handle_cast({sign_tx, Request}, State) ->
+    ok = do_sign_tx(Request, State),
+    {noreply, State};
 handle_cast({make_key, Name, Seed, Encoding, Transform}, State) ->
     NewState = do_make_key(Name, Seed, Encoding, Transform, State),
     {noreply, NewState};
@@ -532,6 +542,7 @@ do_grids(String) ->
     end.
 
 do_grids2({{sign, http}, URL}) ->
+    ok = tell("Making request to ~p", [URL]),
     case httpc:request(URL) of
         {ok, {{_, 200, _}, _, JSON}} -> do_grids_sig(JSON, URL);
         Error                        -> gmc_gui:trouble(Error)
@@ -540,6 +551,7 @@ do_grids2(Instruction) ->
     tell("GRIDS: ~tp", [Instruction]).
 
 do_grids_sig(JSON, URL) ->
+    ok = tell("Received: ~p", [JSON]),
     case zj:decode(JSON) of
         {ok, GRIDS} -> do_grids_sig2(GRIDS#{"url" => URL});
         Error       -> gmc_gui:trouble(Error)
@@ -547,6 +559,8 @@ do_grids_sig(JSON, URL) ->
 
 do_grids_sig2(Request = #{"grids" := 1, "type" := "message"}) ->
     gmc_gui:grids_mess_sig(Request);
+do_grids_sig2(Request = #{"grids" := 1, "type" := "tx"}) ->
+    gmc_gui:grids_mess_sig(Request);
 do_grids_sig2(WTF) ->
     gmc_gui:trouble({trash, WTF}).
 
@@ -608,6 +622,50 @@ eu(N, Size) ->
     <<Bytes/binary, ExtraZeros/binary>>.
 
 
+do_sign_tx(Request = #{"public_id" := ID, "payload" := CallData, "network_id" := NID},
+           #s{wallet = #wallet{keys = Keys}}) ->
+    BinNID = list_to_binary(NID),
+    case lists:keyfind(ID, #key.id, Keys) of
+        #key{pair = #{secret := PrivKey}} ->
+            BinaryTX = list_to_binary(CallData),
+            SignedTX = sign_tx_hash(BinaryTX, PrivKey, BinNID),
+            do_sign_tx2(Request#{"signed" => true, "payload" := SignedTX});
+        false ->
+            gmc_gui:trouble({bad_key, ID})
+    end.
+
+do_sign_tx2(Request = #{"url" := URL}) ->
+    ResponseKeys =
+        ["grids",
+         "chain",
+         "network_id",
+         "type",
+         "public_id",
+         "payload",
+         "signed"],
+    Response = zj:encode(maps:with(ResponseKeys, Request)),
+    case httpc:request(post, {URL, [], "application/json", Response}, [], []) of
+        {ok, {{_, 200, _}, _, JSON}} -> log(info, "Signature posted: ~p", [JSON]);
+        Error                        -> gmc_gui:trouble(Error)
+    end.
+
+sign_tx_hash(Unsigned, PrivKey, NetworkID) ->
+    {ok, TX_Data} = aeser_api_encoder:safe_decode(transaction, Unsigned),
+    {ok, Hash} = eblake2:blake2b(32, TX_Data),
+    NetworkHash = <<NetworkID/binary, Hash/binary>>,
+    Signature = ecu_eddsa:sign_detached(NetworkHash, PrivKey),
+    SigTxType = signed_tx,
+    SigTxVsn  = 1,
+    SigTemplate =
+        [{signatures, [binary]},
+         {transaction, binary}],
+    TX =
+        [{signatures, [Signature]},
+         {transaction, TX_Data}],
+    SignedTX = aeser_chain_objects:serialize(SigTxType, SigTxVsn, SigTemplate, TX),
+    aeser_api_encoder:encode(transaction, SignedTX).
+
+
 do_spend(KeyID, TX, State = #s{wallet = #wallet{keys = Keys}}) ->
     case lists:keyfind(KeyID, #key.id, Keys) of
         #key{pair = #{secret := PrivKey}} ->
diff --git a/src/gmc_gui.erl b/src/gmc_gui.erl
index f64fa9b..28b858a 100644
--- a/src/gmc_gui.erl
+++ b/src/gmc_gui.erl
@@ -804,7 +804,7 @@ is_int(S) ->
 
 
 grids_dialogue(State = #s{frame = Frame, j = J}) ->
-    Dialog = wxDialog:new(Frame, ?wxID_ANY, J("Password")),
+    Dialog = wxDialog:new(Frame, ?wxID_ANY, J("GRIDS URL")),
     Sizer = wxBoxSizer:new(?wxVERTICAL),
     Label = J("GRIDS URL"),
     URL_Sz = wxStaticBoxSizer:new(?wxVERTICAL, Dialog, [{label, J(Label)}]),
@@ -943,9 +943,22 @@ do_grids_mess_sig(Request = #{"public_id" := false},
         Selected ->
             #poa{id = ID} = lists:nth(Selected + 1, Accounts),
             do_grids_mess_sig2(Request#{"public_id" := ID}, State)
+    end;
+do_grids_mess_sig(Request = #{"public_id" := ID}, State = #s{accounts = Accounts}) ->
+    BinID = list_to_binary(ID),
+    case lists:keymember(BinID, #poa.id, Accounts) of
+        true ->
+            do_grids_mess_sig2(Request#{"public_id" := BinID}, State);
+        false ->
+            tell("Request sig from ID we don't have: ~p", [BinID]),
+            tell("Accounts: ~p", [Accounts])
     end.
 
-do_grids_mess_sig2(Request = #{"url" := URL, "public_id" := ID, "payload" := Message},
+do_grids_mess_sig2(Request = #{"grids"     := 1,
+                               "type"      := "message",
+                               "url"       := URL,
+                               "public_id" := ID,
+                               "payload"   := Message},
                    #s{frame = Frame, j = J}) ->
     Dialog = wxDialog:new(Frame, ?wxID_ANY, J("Message Signature Request")),
     Sizer = wxBoxSizer:new(?wxVERTICAL),
@@ -960,7 +973,8 @@ do_grids_mess_sig2(Request = #{"url" := URL, "public_id" := ID, "payload" := Mes
     URL_Tx = wxStaticText:new(Dialog, ?wxID_ANY, URL),
     _ = wxStaticBoxSizer:add(URL_Sz, URL_Tx, zxw:flags(wide)),
     MessSz = wxStaticBoxSizer:new(?wxVERTICAL, Dialog, [{label, J("Message")}]),
-    MessTx = wxStaticText:new(Dialog, ?wxID_ANY, Message),
+    MessStyle = ?wxTE_MULTILINE bor ?wxTE_READONLY,
+    MessTx = wxTextCtrl:new(Dialog, ?wxID_ANY, [{value, Message}, {style, MessStyle}]),
     _ = wxStaticBoxSizer:add(MessSz, MessTx, zxw:flags(wide)),
     ButtSz = wxBoxSizer:new(?wxHORIZONTAL),
     Affirm = wxButton:new(Dialog, ?wxID_OK),
@@ -970,10 +984,10 @@ do_grids_mess_sig2(Request = #{"url" := URL, "public_id" := ID, "payload" := Mes
     _ = wxBoxSizer:add(Sizer, InstTx, zxw:flags(wide)),
     _ = wxBoxSizer:add(Sizer, AcctSz, zxw:flags(wide)),
     _ = wxBoxSizer:add(Sizer, URL_Sz, zxw:flags(wide)),
-    _ = wxBoxSizer:add(Sizer, MessTx, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, MessSz, zxw:flags(wide)),
     _ = wxBoxSizer:add(Sizer, ButtSz, zxw:flags(base)),
     ok = wxDialog:setSizer(Dialog, Sizer),
-    ok = wxFrame:setSize(Dialog, {500, 500}),
+    ok = wxDialog:setSize(Dialog, {500, 500}),
     ok = wxBoxSizer:layout(Sizer),
     ok = wxFrame:center(Dialog),
     ok =
@@ -982,9 +996,54 @@ do_grids_mess_sig2(Request = #{"url" := URL, "public_id" := ID, "payload" := Mes
             ?wxID_CANCEL -> ok
         end,
     wxDialog:destroy(Dialog);
+do_grids_mess_sig2(Request = #{"grids"      := 1,
+                               "type"       := "tx",
+                               "url"        := URL,
+                               "chain"      := Chain,
+                               "network_id" := NetID,
+                               "public_id"  := ID,
+                               "payload"    := CallData},
+                   #s{frame = Frame, j = J}) ->
+    Dialog = wxDialog:new(Frame, ?wxID_ANY, J("Message Signature Request")),
+    Sizer = wxBoxSizer:new(?wxVERTICAL),
+    Instruction =
+        J("The server at the URL below is requesting you sign the following message."),
+    InstTx = wxStaticText:new(Dialog, ?wxID_ANY, Instruction),
+    AcctSz = wxStaticBoxSizer:new(?wxVERTICAL, Dialog, [{label, J("Signature Account")}]),
+    AcctTx = wxStaticText:new(Dialog, ?wxID_ANY, ID),
+    _ = wxStaticBoxSizer:add(AcctSz, AcctTx, zxw:flags(wide)),
+    URL_Label = J("Originating URL"),
+    URL_Sz = wxStaticBoxSizer:new(?wxVERTICAL, Dialog, [{label, URL_Label}]),
+    URL_Tx = wxStaticText:new(Dialog, ?wxID_ANY, URL),
+    _ = wxStaticBoxSizer:add(URL_Sz, URL_Tx, zxw:flags(wide)),
+    MessSz = wxStaticBoxSizer:new(?wxVERTICAL, Dialog, [{label, J("CallData")}]),
+    MessStyle = ?wxTE_MULTILINE bor ?wxTE_READONLY,
+    MessTx = wxTextCtrl:new(Dialog, ?wxID_ANY, [{value, CallData}, {style, MessStyle}]),
+    _ = wxStaticBoxSizer:add(MessSz, MessTx, zxw:flags(wide)),
+    ButtSz = wxBoxSizer:new(?wxHORIZONTAL),
+    Affirm = wxButton:new(Dialog, ?wxID_OK),
+    Cancel = wxButton:new(Dialog, ?wxID_CANCEL),
+    _ = wxBoxSizer:add(ButtSz, Affirm, zxw:flags(wide)),
+    _ = wxBoxSizer:add(ButtSz, Cancel, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, InstTx, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, AcctSz, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, URL_Sz, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, MessSz, zxw:flags(wide)),
+    _ = wxBoxSizer:add(Sizer, ButtSz, zxw:flags(base)),
+    ok = wxDialog:setSizer(Dialog, Sizer),
+    ok = wxDialog:setSize(Dialog, {500, 500}),
+    ok = wxBoxSizer:layout(Sizer),
+    ok = wxFrame:center(Dialog),
+    ok =
+        case wxDialog:showModal(Dialog) of
+            ?wxID_OK     -> gmc_con:sign_tx(Request);
+            ?wxID_CANCEL -> ok
+        end,
+    wxDialog:destroy(Dialog);
 do_grids_mess_sig2(BadRequest, _) ->
     tell("Bad request: ~tp", [BadRequest]).
     
+    
 
 
 %%% Helpers