diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8554540501..f12eaa4203 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## Pending
+
+BREAKING CHANGES
+
+FEATURES
+
+IMPROVEMENTS
+* bank module uses go-wire codec instead of 'encoding/json'
+* auth module uses go-wire codec instead of 'encoding/json'
+
+FIXES
+
 ## 0.18.1
 
 BREAKING CHANGES
diff --git a/x/auth/msgs.go b/x/auth/msgs.go
index c449b837b1..3eb5cc8ba2 100644
--- a/x/auth/msgs.go
+++ b/x/auth/msgs.go
@@ -1,8 +1,6 @@
 package auth
 
 import (
-	"encoding/json"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	crypto "github.com/tendermint/go-crypto"
 )
@@ -30,7 +28,7 @@ func (msg MsgChangeKey) ValidateBasic() sdk.Error {
 
 // Implements Msg.
 func (msg MsgChangeKey) GetSignBytes() []byte {
-	b, err := json.Marshal(msg) // XXX: ensure some canonical form
+	b, err := msgCdc.MarshalJSON(msg) // XXX: ensure some canonical form
 	if err != nil {
 		panic(err)
 	}
diff --git a/x/auth/stdtx.go b/x/auth/stdtx.go
index bc01b01490..4858ae0b43 100644
--- a/x/auth/stdtx.go
+++ b/x/auth/stdtx.go
@@ -1,8 +1,6 @@
 package auth
 
 import (
-	"encoding/json"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	crypto "github.com/tendermint/go-crypto"
 )
@@ -70,7 +68,7 @@ func (fee StdFee) Bytes() []byte {
 	if len(fee.Amount) == 0 {
 		fee.Amount = sdk.Coins{}
 	}
-	bz, err := json.Marshal(fee) // TODO
+	bz, err := msgCdc.MarshalJSON(fee) // TODO
 	if err != nil {
 		panic(err)
 	}
@@ -95,7 +93,7 @@ type StdSignDoc struct {
 // StdSignBytes returns the bytes to sign for a transaction.
 // TODO: change the API to just take a chainID and StdTx ?
 func StdSignBytes(chainID string, sequences []int64, fee StdFee, msg sdk.Msg) []byte {
-	bz, err := json.Marshal(StdSignDoc{
+	bz, err := msgCdc.MarshalJSON(StdSignDoc{
 		ChainID:   chainID,
 		Sequences: sequences,
 		FeeBytes:  fee.Bytes(),
diff --git a/x/auth/wire.go b/x/auth/wire.go
index 42b34b96d5..309464c864 100644
--- a/x/auth/wire.go
+++ b/x/auth/wire.go
@@ -10,3 +10,10 @@ func RegisterWire(cdc *wire.Codec) {
 	cdc.RegisterConcrete(&BaseAccount{}, "auth/Account", nil)
 	cdc.RegisterConcrete(MsgChangeKey{}, "auth/ChangeKey", nil)
 }
+
+var msgCdc = wire.NewCodec()
+
+func init() {
+	RegisterWire(msgCdc)
+	wire.RegisterCrypto(msgCdc)
+}
diff --git a/x/bank/client/rest/sendtx.go b/x/bank/client/rest/sendtx.go
index 916aa08fe1..defed3f144 100644
--- a/x/bank/client/rest/sendtx.go
+++ b/x/bank/client/rest/sendtx.go
@@ -11,6 +11,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client/context"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/wire"
+	"github.com/cosmos/cosmos-sdk/x/bank"
 	"github.com/cosmos/cosmos-sdk/x/bank/client"
 )
 
@@ -29,6 +30,12 @@ type sendBody struct {
 	Sequence         int64     `json:"sequence"`
 }
 
+var msgCdc = wire.NewCodec()
+
+func init() {
+	bank.RegisterWire(msgCdc)
+}
+
 // SendRequestHandlerFn - http request handler to send coins to a address
 func SendRequestHandlerFn(cdc *wire.Codec, kb keys.Keybase, ctx context.CoreContext) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
@@ -43,7 +50,7 @@ func SendRequestHandlerFn(cdc *wire.Codec, kb keys.Keybase, ctx context.CoreCont
 			w.Write([]byte(err.Error()))
 			return
 		}
-		err = json.Unmarshal(body, &m)
+		err = msgCdc.UnmarshalJSON(body, &m)
 		if err != nil {
 			w.WriteHeader(http.StatusBadRequest)
 			w.Write([]byte(err.Error()))
diff --git a/x/bank/msgs.go b/x/bank/msgs.go
index de7f2a8b15..7836056de0 100644
--- a/x/bank/msgs.go
+++ b/x/bank/msgs.go
@@ -1,8 +1,6 @@
 package bank
 
 import (
-	"encoding/json"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
@@ -55,7 +53,7 @@ func (msg MsgSend) ValidateBasic() sdk.Error {
 
 // Implements Msg.
 func (msg MsgSend) GetSignBytes() []byte {
-	b, err := json.Marshal(msg) // XXX: ensure some canonical form
+	b, err := msgCdc.MarshalJSON(msg) // XXX: ensure some canonical form
 	if err != nil {
 		panic(err)
 	}
@@ -104,7 +102,7 @@ func (msg MsgIssue) ValidateBasic() sdk.Error {
 
 // Implements Msg.
 func (msg MsgIssue) GetSignBytes() []byte {
-	b, err := json.Marshal(msg) // XXX: ensure some canonical form
+	b, err := msgCdc.MarshalJSON(msg) // XXX: ensure some canonical form
 	if err != nil {
 		panic(err)
 	}
diff --git a/x/bank/msgs_test.go b/x/bank/msgs_test.go
index 78de01f400..8f9791c8d7 100644
--- a/x/bank/msgs_test.go
+++ b/x/bank/msgs_test.go
@@ -186,8 +186,14 @@ func TestMsgSendGetSignBytes(t *testing.T) {
 		Outputs: []Output{NewOutput(addr2, coins)},
 	}
 	res := msg.GetSignBytes()
+
+	unmarshaledMsg := &MsgSend{}
+	msgCdc.UnmarshalJSON(res, unmarshaledMsg)
+	assert.Equal(t, &msg, unmarshaledMsg)
+
 	// TODO bad results
-	assert.Equal(t, string(res), `{"inputs":[{"address":"696E707574","coins":[{"denom":"atom","amount":10}]}],"outputs":[{"address":"6F7574707574","coins":[{"denom":"atom","amount":10}]}]}`)
+	expected := `{"type":"EAFDE32A2C87F8","value":{"inputs":[{"address":"696E707574","coins":[{"denom":"atom","amount":10}]}],"outputs":[{"address":"6F7574707574","coins":[{"denom":"atom","amount":10}]}]}}`
+	assert.Equal(t, expected, string(res))
 }
 
 func TestMsgSendGetSigners(t *testing.T) {
@@ -255,8 +261,14 @@ func TestMsgIssueGetSignBytes(t *testing.T) {
 		Outputs: []Output{NewOutput(addr, coins)},
 	}
 	res := msg.GetSignBytes()
+
+	unmarshaledMsg := &MsgIssue{}
+	msgCdc.UnmarshalJSON(res, unmarshaledMsg)
+	assert.Equal(t, &msg, unmarshaledMsg)
+
 	// TODO bad results
-	assert.Equal(t, string(res), `{"banker":"696E707574","outputs":[{"address":"6C6F616E2D66726F6D2D62616E6B","coins":[{"denom":"atom","amount":10}]}]}`)
+	expected := `{"type":"72E617C06ABAD0","value":{"banker":"696E707574","outputs":[{"address":"6C6F616E2D66726F6D2D62616E6B","coins":[{"denom":"atom","amount":10}]}]}}`
+	assert.Equal(t, expected, string(res))
 }
 
 func TestMsgIssueGetSigners(t *testing.T) {
diff --git a/x/bank/wire.go b/x/bank/wire.go
index fdb6c252b5..f468d3e530 100644
--- a/x/bank/wire.go
+++ b/x/bank/wire.go
@@ -9,3 +9,9 @@ func RegisterWire(cdc *wire.Codec) {
 	cdc.RegisterConcrete(MsgSend{}, "cosmos-sdk/Send", nil)
 	cdc.RegisterConcrete(MsgIssue{}, "cosmos-sdk/Issue", nil)
 }
+
+var msgCdc = wire.NewCodec()
+
+func init() {
+	RegisterWire(msgCdc)
+}
diff --git a/x/stake/msg.go b/x/stake/msg.go
index 1cbf31c82d..67d9597cac 100644
--- a/x/stake/msg.go
+++ b/x/stake/msg.go
@@ -1,10 +1,7 @@
 package stake
 
 import (
-	"encoding/json"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/wire"
 	crypto "github.com/tendermint/go-crypto"
 )
 
@@ -20,12 +17,6 @@ const StakingToken = "steak"
 //Verify interface at compile time
 var _, _, _, _ sdk.Msg = &MsgDeclareCandidacy{}, &MsgEditCandidacy{}, &MsgDelegate{}, &MsgUnbond{}
 
-var msgCdc = wire.NewCodec()
-
-func init() {
-	wire.RegisterCrypto(msgCdc)
-}
-
 //______________________________________________________________________
 
 // MsgDeclareCandidacy - struct for unbonding transactions
@@ -98,7 +89,7 @@ func (msg MsgEditCandidacy) GetSigners() []sdk.Address {
 
 // get the bytes for the message signer to sign on
 func (msg MsgEditCandidacy) GetSignBytes() []byte {
-	b, err := json.Marshal(msg)
+	b, err := msgCdc.MarshalJSON(msg)
 	if err != nil {
 		panic(err)
 	}
@@ -142,7 +133,7 @@ func (msg MsgDelegate) GetSigners() []sdk.Address {
 
 // get the bytes for the message signer to sign on
 func (msg MsgDelegate) GetSignBytes() []byte {
-	b, err := json.Marshal(msg)
+	b, err := msgCdc.MarshalJSON(msg)
 	if err != nil {
 		panic(err)
 	}
@@ -189,7 +180,7 @@ func (msg MsgUnbond) GetSigners() []sdk.Address { return []sdk.Address{msg.Deleg
 
 // get the bytes for the message signer to sign on
 func (msg MsgUnbond) GetSignBytes() []byte {
-	b, err := json.Marshal(msg)
+	b, err := msgCdc.MarshalJSON(msg)
 	if err != nil {
 		panic(err)
 	}
diff --git a/x/stake/params.go b/x/stake/params.go
index ace39935c3..026bd871f1 100644
--- a/x/stake/params.go
+++ b/x/stake/params.go
@@ -18,8 +18,8 @@ type Params struct {
 }
 
 func (p Params) equal(p2 Params) bool {
-	bz1 := cdcEmpty.MustMarshalBinary(&p)
-	bz2 := cdcEmpty.MustMarshalBinary(&p2)
+	bz1 := msgCdc.MustMarshalBinary(&p)
+	bz2 := msgCdc.MustMarshalBinary(&p2)
 	return bytes.Equal(bz1, bz2)
 }
 
diff --git a/x/stake/pool.go b/x/stake/pool.go
index 0b320432ed..ba1890ce55 100644
--- a/x/stake/pool.go
+++ b/x/stake/pool.go
@@ -25,8 +25,8 @@ type Pool struct {
 }
 
 func (p Pool) equal(p2 Pool) bool {
-	bz1 := cdcEmpty.MustMarshalBinary(&p)
-	bz2 := cdcEmpty.MustMarshalBinary(&p2)
+	bz1 := msgCdc.MustMarshalBinary(&p)
+	bz2 := msgCdc.MustMarshalBinary(&p2)
 	return bytes.Equal(bz1, bz2)
 }
 
diff --git a/x/stake/wire.go b/x/stake/wire.go
index 6e6e382606..fb1a1c8867 100644
--- a/x/stake/wire.go
+++ b/x/stake/wire.go
@@ -12,4 +12,9 @@ func RegisterWire(cdc *wire.Codec) {
 	cdc.RegisterConcrete(MsgUnbond{}, "cosmos-sdk/MsgUnbond", nil)
 }
 
-var cdcEmpty = wire.NewCodec()
+var msgCdc = wire.NewCodec()
+
+func init() {
+	RegisterWire(msgCdc)
+	wire.RegisterCrypto(msgCdc)
+}