diff --git a/errors/common.go b/errors/common.go
index 73a0f6a507..fdc04ea8ad 100644
--- a/errors/common.go
+++ b/errors/common.go
@@ -16,21 +16,14 @@ import (
 var (
 	errDecoding          = rawerr.New("Error decoding input")
 	errUnauthorized      = rawerr.New("Unauthorized")
-	errInvalidAddress    = rawerr.New("Invalid Address")
-	errInvalidCoins      = rawerr.New("Invalid Coins")
-	errInvalidFormat     = rawerr.New("Invalid Format")
-	errInvalidSequence   = rawerr.New("Invalid Sequence")
 	errInvalidSignature  = rawerr.New("Invalid Signature")
-	errInsufficientFees  = rawerr.New("Insufficient Fees")
-	errInsufficientFunds = rawerr.New("Insufficient Funds")
-	errNoInputs          = rawerr.New("No Input Coins")
-	errNoOutputs         = rawerr.New("No Output Coins")
 	errTooLarge          = rawerr.New("Input size too large")
 	errMissingSignature  = rawerr.New("Signature missing")
 	errTooManySignatures = rawerr.New("Too many signatures")
 	errNoChain           = rawerr.New("No chain id provided")
 	errWrongChain        = rawerr.New("Wrong chain for tx")
 	errUnknownTxType     = rawerr.New("Tx type unknown")
+	errInvalidFormat     = rawerr.New("Invalid format")
 )
 
 func ErrUnknownTxType(tx basecoin.Tx) TMError {
@@ -38,11 +31,19 @@ func ErrUnknownTxType(tx basecoin.Tx) TMError {
 	w := errors.Wrap(errUnknownTxType, msg)
 	return WithCode(w, abci.CodeType_UnknownRequest)
 }
-
 func IsUnknownTxTypeErr(err error) bool {
 	return IsSameError(errUnknownTxType, err)
 }
 
+func ErrInvalidFormat(tx basecoin.Tx) TMError {
+	msg := fmt.Sprintf("%T", tx.Unwrap())
+	w := errors.Wrap(errInvalidFormat, msg)
+	return WithCode(w, abci.CodeType_UnknownRequest)
+}
+func IsInvalidFormatErr(err error) bool {
+	return IsSameError(errInvalidFormat, err)
+}
+
 func ErrInternal(msg string) TMError {
 	return New(msg, abci.CodeType_InternalError)
 }
@@ -55,7 +56,6 @@ func IsInternalErr(err error) bool {
 func ErrDecoding() TMError {
 	return WithCode(errDecoding, abci.CodeType_EncodingError)
 }
-
 func IsDecodingErr(err error) bool {
 	return IsSameError(errDecoding, err)
 }
@@ -73,7 +73,6 @@ func IsUnauthorizedErr(err error) bool {
 func ErrMissingSignature() TMError {
 	return WithCode(errMissingSignature, abci.CodeType_Unauthorized)
 }
-
 func IsMissingSignatureErr(err error) bool {
 	return IsSameError(errMissingSignature, err)
 }
@@ -81,7 +80,6 @@ func IsMissingSignatureErr(err error) bool {
 func ErrTooManySignatures() TMError {
 	return WithCode(errTooManySignatures, abci.CodeType_Unauthorized)
 }
-
 func IsTooManySignaturesErr(err error) bool {
 	return IsSameError(errTooManySignatures, err)
 }
@@ -89,7 +87,6 @@ func IsTooManySignaturesErr(err error) bool {
 func ErrInvalidSignature() TMError {
 	return WithCode(errInvalidSignature, abci.CodeType_Unauthorized)
 }
-
 func IsInvalidSignatureErr(err error) bool {
 	return IsSameError(errInvalidSignature, err)
 }
@@ -97,7 +94,6 @@ func IsInvalidSignatureErr(err error) bool {
 func ErrNoChain() TMError {
 	return WithCode(errNoChain, abci.CodeType_Unauthorized)
 }
-
 func IsNoChainErr(err error) bool {
 	return IsSameError(errNoChain, err)
 }
@@ -106,47 +102,13 @@ func ErrWrongChain(chain string) TMError {
 	msg := errors.Wrap(errWrongChain, chain)
 	return WithCode(msg, abci.CodeType_Unauthorized)
 }
-
 func IsWrongChainErr(err error) bool {
 	return IsSameError(errWrongChain, err)
 }
 
-func InvalidAddress() TMError {
-	return WithCode(errInvalidAddress, abci.CodeType_BaseInvalidInput)
-}
-
-func InvalidCoins() TMError {
-	return WithCode(errInvalidCoins, abci.CodeType_BaseInvalidInput)
-}
-
-func InvalidFormat() TMError {
-	return WithCode(errInvalidFormat, abci.CodeType_BaseInvalidInput)
-}
-
-func InvalidSequence() TMError {
-	return WithCode(errInvalidSequence, abci.CodeType_BaseInvalidInput)
-}
-
-func InsufficientFees() TMError {
-	return WithCode(errInsufficientFees, abci.CodeType_BaseInvalidInput)
-}
-
-func InsufficientFunds() TMError {
-	return WithCode(errInsufficientFunds, abci.CodeType_BaseInvalidInput)
-}
-
-func NoInputs() TMError {
-	return WithCode(errNoInputs, abci.CodeType_BaseInvalidInput)
-}
-
-func NoOutputs() TMError {
-	return WithCode(errNoOutputs, abci.CodeType_BaseInvalidOutput)
-}
-
 func ErrTooLarge() TMError {
 	return WithCode(errTooLarge, abci.CodeType_EncodingError)
 }
-
 func IsTooLargeErr(err error) bool {
 	return IsSameError(errTooLarge, err)
 }
diff --git a/modules/coin/errors.go b/modules/coin/errors.go
new file mode 100644
index 0000000000..d9b2fea6c0
--- /dev/null
+++ b/modules/coin/errors.go
@@ -0,0 +1,88 @@
+package coin
+
+import (
+	rawerr "errors"
+
+	abci "github.com/tendermint/abci/types"
+	"github.com/tendermint/basecoin/errors"
+)
+
+var (
+	errNoAccount         = rawerr.New("No such account")
+	errInsufficientFunds = rawerr.New("Insufficient Funds")
+	errNoInputs          = rawerr.New("No Input Coins")
+	errNoOutputs         = rawerr.New("No Output Coins")
+	errInvalidAddress    = rawerr.New("Invalid Address")
+	errInvalidCoins      = rawerr.New("Invalid Coins")
+	errInvalidSequence   = rawerr.New("Invalid Sequence")
+)
+
+var (
+	invalidInput   = abci.CodeType_BaseInvalidInput
+	invalidOutput  = abci.CodeType_BaseInvalidOutput
+	unknownAddress = abci.CodeType_BaseUnknownAddress
+)
+
+// here are some generic handlers to grab classes of errors based on code
+func IsInputErr(err error) bool {
+	return errors.HasErrorCode(err, invalidInput)
+}
+func IsOutputErr(err error) bool {
+	return errors.HasErrorCode(err, invalidOutput)
+}
+func IsAddressErr(err error) bool {
+	return errors.HasErrorCode(err, unknownAddress)
+}
+func IsCoinErr(err error) bool {
+	return err != nil && (IsInputErr(err) || IsOutputErr(err) || IsAddressErr(err))
+}
+
+func ErrNoAccount() errors.TMError {
+	return errors.WithCode(errNoAccount, unknownAddress)
+}
+
+func IsNoAccountErr(err error) bool {
+	return errors.IsSameError(errNoAccount, err)
+}
+
+func ErrInvalidAddress() errors.TMError {
+	return errors.WithCode(errInvalidAddress, invalidInput)
+}
+func IsInvalidAddressErr(err error) bool {
+	return errors.IsSameError(errInvalidAddress, err)
+}
+
+func ErrInvalidCoins() errors.TMError {
+	return errors.WithCode(errInvalidCoins, invalidInput)
+}
+func IsInvalidCoinsErr(err error) bool {
+	return errors.IsSameError(errInvalidCoins, err)
+}
+
+func ErrInvalidSequence() errors.TMError {
+	return errors.WithCode(errInvalidSequence, invalidInput)
+}
+func IsInvalidSequenceErr(err error) bool {
+	return errors.IsSameError(errInvalidSequence, err)
+}
+
+func ErrInsufficientFunds() errors.TMError {
+	return errors.WithCode(errInsufficientFunds, invalidInput)
+}
+func IsInsufficientFundsErr(err error) bool {
+	return errors.IsSameError(errInsufficientFunds, err)
+}
+
+func ErrNoInputs() errors.TMError {
+	return errors.WithCode(errNoInputs, invalidInput)
+}
+func IsNoInputsErr(err error) bool {
+	return errors.IsSameError(errNoInputs, err)
+}
+
+func ErrNoOutputs() errors.TMError {
+	return errors.WithCode(errNoOutputs, invalidOutput)
+}
+func IsNoOutputsErr(err error) bool {
+	return errors.IsSameError(errNoOutputs, err)
+}
diff --git a/modules/coin/handler.go b/modules/coin/handler.go
index 7947283084..0e1740f1c1 100644
--- a/modules/coin/handler.go
+++ b/modules/coin/handler.go
@@ -11,10 +11,18 @@ const (
 )
 
 // Handler writes
-type Handler struct{}
+type Handler struct {
+	Accountant
+}
 
 var _ basecoin.Handler = Handler{}
 
+func NewHandler() Handler {
+	return Handler{
+		Accountant: Accountant{Prefix: []byte(NameCoin + "/")},
+	}
+}
+
 func (_ Handler) Name() string {
 	return NameCoin
 }
@@ -47,7 +55,7 @@ func checkTx(ctx basecoin.Context, tx basecoin.Tx) (send SendTx, err error) {
 	// check if the tx is proper type and valid
 	send, ok := tx.Unwrap().(SendTx)
 	if !ok {
-		return send, errors.UnknownTxType(tx)
+		return send, errors.ErrInvalidFormat(tx)
 	}
 	err = send.ValidateBasic()
 	if err != nil {
@@ -57,7 +65,7 @@ func checkTx(ctx basecoin.Context, tx basecoin.Tx) (send SendTx, err error) {
 	// check if all inputs have permission
 	for _, in := range send.Inputs {
 		if !ctx.HasPermission(in.Address) {
-			return send, errors.Unauthorized()
+			return send, errors.ErrUnauthorized()
 		}
 	}
 	return send, nil
diff --git a/modules/coin/handler_test.go b/modules/coin/handler_test.go
index f9a4c490bb..52560f128b 100644
--- a/modules/coin/handler_test.go
+++ b/modules/coin/handler_test.go
@@ -12,7 +12,7 @@ import (
 func TestHandlerPermissions(t *testing.T) {
 	assert := assert.New(t)
 	// TODO: need to update this when we actually have token store
-	h := Handler{}
+	h := NewHandler()
 
 	// these are all valid, except for minusCoins
 	addr1 := basecoin.Actor{App: "coin", Address: []byte{1, 2}}
diff --git a/modules/coin/store.go b/modules/coin/store.go
index 2b217d4f01..bede0c009c 100644
--- a/modules/coin/store.go
+++ b/modules/coin/store.go
@@ -15,8 +15,12 @@ type Accountant struct {
 }
 
 func (a Accountant) GetAccount(store types.KVStore, addr basecoin.Actor) (Account, error) {
-	// TODO: how to handle empty accounts??
-	return loadAccount(store, a.makeKey(addr))
+	acct, err := loadAccount(store, a.makeKey(addr))
+	// for empty accounts, don't return an error, but rather an empty account
+	if IsNoAccountErr(err) {
+		err = nil
+	}
+	return acct, err
 }
 
 // CheckCoins makes sure there are funds, but doesn't change anything
@@ -47,14 +51,14 @@ func (a Accountant) updateCoins(store types.KVStore, addr basecoin.Actor, coins
 
 	// check sequence
 	if seq != acct.Sequence+1 {
-		return acct, errors.InvalidSequence()
+		return acct, ErrInvalidSequence()
 	}
 	acct.Sequence += 1
 
 	// check amount
 	final := acct.Coins.Minus(coins)
 	if !final.IsNonnegative() {
-		return acct, errors.InsufficientFunds()
+		return acct, ErrInsufficientFunds()
 	}
 
 	acct.Coins = final
@@ -77,13 +81,12 @@ type Account struct {
 func loadAccount(store types.KVStore, key []byte) (acct Account, err error) {
 	data := store.Get(key)
 	if len(data) == 0 {
-		// TODO: error or empty????
-		return acct, errors.InternalError("No account found")
+		return acct, ErrNoAccount()
 	}
 	err = wire.ReadBinaryBytes(data, &acct)
 	if err != nil {
 		msg := fmt.Sprintf("Error reading account %X", key)
-		return acct, errors.InternalError(msg)
+		return acct, errors.ErrInternal(msg)
 	}
 	return acct, nil
 }
diff --git a/modules/coin/tx.go b/modules/coin/tx.go
index 711362dfcd..e40967e48e 100644
--- a/modules/coin/tx.go
+++ b/modules/coin/tx.go
@@ -5,7 +5,6 @@ import (
 
 	"github.com/tendermint/basecoin"
 
-	"github.com/tendermint/basecoin/errors"
 	"github.com/tendermint/basecoin/types"
 )
 
@@ -29,20 +28,20 @@ type TxInput struct {
 
 func (txIn TxInput) ValidateBasic() error {
 	if txIn.Address.App == "" {
-		return errors.InvalidAddress()
+		return ErrInvalidAddress()
 	}
 	// TODO: knowledge of app-specific codings?
 	if len(txIn.Address.Address) == 0 {
-		return errors.InvalidAddress()
+		return ErrInvalidAddress()
 	}
 	if !txIn.Coins.IsValid() {
-		return errors.InvalidCoins()
+		return ErrInvalidCoins()
 	}
 	if !txIn.Coins.IsPositive() {
-		return errors.InvalidCoins()
+		return ErrInvalidCoins()
 	}
 	if txIn.Sequence <= 0 {
-		return errors.InvalidSequence()
+		return ErrInvalidSequence()
 	}
 	return nil
 }
@@ -69,17 +68,17 @@ type TxOutput struct {
 
 func (txOut TxOutput) ValidateBasic() error {
 	if txOut.Address.App == "" {
-		return errors.InvalidAddress()
+		return ErrInvalidAddress()
 	}
 	// TODO: knowledge of app-specific codings?
 	if len(txOut.Address.Address) == 0 {
-		return errors.InvalidAddress()
+		return ErrInvalidAddress()
 	}
 	if !txOut.Coins.IsValid() {
-		return errors.InvalidCoins()
+		return ErrInvalidCoins()
 	}
 	if !txOut.Coins.IsPositive() {
-		return errors.InvalidCoins()
+		return ErrInvalidCoins()
 	}
 	return nil
 }
@@ -109,10 +108,10 @@ func (tx SendTx) ValidateBasic() error {
 	// this just makes sure all the inputs and outputs are properly formatted,
 	// not that they actually have the money inside
 	if len(tx.Inputs) == 0 {
-		return errors.NoInputs()
+		return ErrNoInputs()
 	}
 	if len(tx.Outputs) == 0 {
-		return errors.NoOutputs()
+		return ErrNoOutputs()
 	}
 	// make sure all inputs and outputs are individually valid
 	var totalIn, totalOut types.Coins
@@ -130,7 +129,7 @@ func (tx SendTx) ValidateBasic() error {
 	}
 	// make sure inputs and outputs match
 	if !totalIn.IsEqual(totalOut) {
-		return errors.InvalidCoins()
+		return ErrInvalidCoins()
 	}
 	return nil
 }
diff --git a/modules/fee/errors.go b/modules/fee/errors.go
new file mode 100644
index 0000000000..0b6d7fcaf8
--- /dev/null
+++ b/modules/fee/errors.go
@@ -0,0 +1,19 @@
+package fee
+
+import (
+	rawerr "errors"
+
+	abci "github.com/tendermint/abci/types"
+	"github.com/tendermint/basecoin/errors"
+)
+
+var (
+	errInsufficientFees = rawerr.New("Insufficient Fees")
+)
+
+func ErrInsufficientFees() errors.TMError {
+	return errors.WithCode(errInsufficientFees, abci.CodeType_BaseInvalidInput)
+}
+func IsInsufficientFeesErr(err error) bool {
+	return errors.IsSameError(errInsufficientFees, err)
+}
diff --git a/modules/fee/handler.go b/modules/fee/handler.go
index 18b82812b7..1b4556ef4e 100644
--- a/modules/fee/handler.go
+++ b/modules/fee/handler.go
@@ -36,16 +36,16 @@ var _ stack.Middleware = SimpleFeeHandler{}
 func (h SimpleFeeHandler) CheckTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Checker) (res basecoin.Result, err error) {
 	feeTx, ok := tx.Unwrap().(*Fee)
 	if !ok {
-		return res, errors.InvalidFormat()
+		return res, errors.ErrInvalidFormat(tx)
 	}
 
 	fees := types.Coins{feeTx.Fee}
 	if !fees.IsGTE(h.MinFee) {
-		return res, errors.InsufficientFees()
+		return res, ErrInsufficientFees()
 	}
 
 	if !ctx.HasPermission(feeTx.Payer) {
-		return res, errors.Unauthorized()
+		return res, errors.ErrUnauthorized()
 	}
 
 	_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
@@ -59,16 +59,16 @@ func (h SimpleFeeHandler) CheckTx(ctx basecoin.Context, store types.KVStore, tx
 func (h SimpleFeeHandler) DeliverTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Deliver) (res basecoin.Result, err error) {
 	feeTx, ok := tx.Unwrap().(*Fee)
 	if !ok {
-		return res, errors.InvalidFormat()
+		return res, errors.ErrInvalidFormat(tx)
 	}
 
 	fees := types.Coins{feeTx.Fee}
 	if !fees.IsGTE(h.MinFee) {
-		return res, errors.InsufficientFees()
+		return res, ErrInsufficientFees()
 	}
 
 	if !ctx.HasPermission(feeTx.Payer) {
-		return res, errors.Unauthorized()
+		return res, errors.ErrUnauthorized()
 	}
 
 	_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
diff --git a/stack/chain.go b/stack/chain.go
index f351c24864..ef174495b8 100644
--- a/stack/chain.go
+++ b/stack/chain.go
@@ -42,10 +42,10 @@ func (c Chain) DeliverTx(ctx basecoin.Context, store types.KVStore, tx basecoin.
 func (c Chain) checkChain(tx basecoin.Tx) (basecoin.Tx, error) {
 	ctx, ok := tx.Unwrap().(*txs.Chain)
 	if !ok {
-		return tx, errors.NoChain()
+		return tx, errors.ErrNoChain()
 	}
 	if ctx.ChainID != c.ChainID {
-		return tx, errors.WrongChain(ctx.ChainID)
+		return tx, errors.ErrWrongChain(ctx.ChainID)
 	}
 	return ctx.Tx, nil
 }
diff --git a/stack/chain_test.go b/stack/chain_test.go
index b41bd0b57b..a17b6bd481 100644
--- a/stack/chain_test.go
+++ b/stack/chain_test.go
@@ -25,7 +25,7 @@ func TestChain(t *testing.T) {
 		errorMsg string
 	}{
 		{txs.NewChain(chainID, raw).Wrap(), true, ""},
-		{txs.NewChain("someone-else", raw).Wrap(), false, "Tx belongs to different chain - someone-else"},
+		{txs.NewChain("someone-else", raw).Wrap(), false, "someone-else"},
 		{raw, false, "No chain id provided"},
 	}
 
@@ -47,7 +47,7 @@ func TestChain(t *testing.T) {
 			assert.Equal(msg, res.Log, i)
 		} else {
 			if assert.NotNil(err, i) {
-				assert.Equal(tc.errorMsg, err.Error(), i)
+				assert.Contains(err.Error(), tc.errorMsg, i)
 			}
 		}
 
@@ -58,7 +58,7 @@ func TestChain(t *testing.T) {
 			assert.Equal(msg, res.Log, i)
 		} else {
 			if assert.NotNil(err, i) {
-				assert.Equal(tc.errorMsg, err.Error(), i)
+				assert.Contains(err.Error(), tc.errorMsg, i)
 			}
 		}
 	}
diff --git a/stack/helperware.go b/stack/helperware.go
index 15201b892f..ec2282ac84 100644
--- a/stack/helperware.go
+++ b/stack/helperware.go
@@ -25,14 +25,14 @@ func (_ CheckMiddleware) Name() string {
 
 func (p CheckMiddleware) CheckTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Checker) (res basecoin.Result, err error) {
 	if !ctx.HasPermission(p.Required) {
-		return res, errors.Unauthorized()
+		return res, errors.ErrUnauthorized()
 	}
 	return next.CheckTx(ctx, store, tx)
 }
 
 func (p CheckMiddleware) DeliverTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Deliver) (res basecoin.Result, err error) {
 	if !ctx.HasPermission(p.Required) {
-		return res, errors.Unauthorized()
+		return res, errors.ErrUnauthorized()
 	}
 	return next.DeliverTx(ctx, store, tx)
 }
diff --git a/stack/middleware_test.go b/stack/middleware_test.go
index 82f802ebf4..eed6a183e5 100644
--- a/stack/middleware_test.go
+++ b/stack/middleware_test.go
@@ -31,12 +31,12 @@ func TestPermissionSandbox(t *testing.T) {
 		grant       basecoin.Actor
 		require     basecoin.Actor
 		expectedRes data.Bytes
-		expectedErr error
+		expected    func(error) bool
 	}{
 		{grantee, grantee, rawBytes, nil},
-		{grantee, grantee2, nil, errors.Unauthorized()},
-		{grantee, signer, nil, errors.Unauthorized()},
-		{signer, signer, nil, errors.InternalError("panic")},
+		{grantee, grantee2, nil, errors.IsUnauthorizedErr},
+		{grantee, signer, nil, errors.IsUnauthorizedErr},
+		{signer, signer, nil, errors.IsInternalErr},
 	}
 
 	for i, tc := range cases {
@@ -47,24 +47,22 @@ func TestPermissionSandbox(t *testing.T) {
 		).Use(EchoHandler{})
 
 		res, err := app.CheckTx(ctx, store, raw)
-		checkPerm(t, i, tc.expectedRes, tc.expectedErr, res, err)
+		checkPerm(t, i, tc.expectedRes, tc.expected, res, err)
 
 		res, err = app.DeliverTx(ctx, store, raw)
-		checkPerm(t, i, tc.expectedRes, tc.expectedErr, res, err)
+		checkPerm(t, i, tc.expectedRes, tc.expected, res, err)
 	}
 }
 
-func checkPerm(t *testing.T, idx int, data []byte, expected error, res basecoin.Result, err error) {
+func checkPerm(t *testing.T, idx int, data []byte, check func(error) bool, res basecoin.Result, err error) {
 	assert := assert.New(t)
 
-	if expected == nil {
+	if len(data) > 0 {
 		assert.Nil(err, "%d: %+v", idx, err)
 		assert.EqualValues(data, res.Data)
 	} else {
 		assert.NotNil(err, "%d", idx)
 		// check error code!
-		shouldCode := errors.Wrap(expected).ErrorCode()
-		isCode := errors.Wrap(err).ErrorCode()
-		assert.Equal(shouldCode, isCode, "%d: %+v", idx, err)
+		assert.True(check(err), "%d: %+v", idx, err)
 	}
 }
diff --git a/stack/recovery.go b/stack/recovery.go
index a572534fb2..b6e84496c6 100644
--- a/stack/recovery.go
+++ b/stack/recovery.go
@@ -45,5 +45,5 @@ func normalizePanic(p interface{}) error {
 		return errors.Wrap(err)
 	}
 	msg := fmt.Sprintf("%v", p)
-	return errors.InternalError(msg)
+	return errors.ErrInternal(msg)
 }
diff --git a/stack/signature.go b/stack/signature.go
index 13846e516a..049351dd10 100644
--- a/stack/signature.go
+++ b/stack/signature.go
@@ -61,7 +61,7 @@ func addSigners(ctx basecoin.Context, sigs []crypto.PubKey) basecoin.Context {
 func getSigners(tx basecoin.Tx) ([]crypto.PubKey, basecoin.Tx, error) {
 	stx, ok := tx.Unwrap().(Signed)
 	if !ok {
-		return nil, basecoin.Tx{}, errors.Unauthorized()
+		return nil, basecoin.Tx{}, errors.ErrUnauthorized()
 	}
 	sig, err := stx.Signers()
 	return sig, stx.Next(), err
diff --git a/txs/base.go b/txs/base.go
index c2463b83c9..fcbb17899a 100644
--- a/txs/base.go
+++ b/txs/base.go
@@ -50,7 +50,7 @@ func (r Raw) Wrap() basecoin.Tx {
 
 func (r Raw) ValidateBasic() error {
 	if len(r.Bytes) > rawMaxSize {
-		return errors.TooLarge()
+		return errors.ErrTooLarge()
 	}
 	return nil
 }
diff --git a/txs/sigs.go b/txs/sigs.go
index 5550f262f9..699b6aa520 100644
--- a/txs/sigs.go
+++ b/txs/sigs.go
@@ -66,7 +66,7 @@ func (s *OneSig) Next() basecoin.Tx {
 func (s *OneSig) ValidateBasic() error {
 	// TODO: VerifyBytes here, we do it in Signers?
 	if s.Empty() || !s.Pubkey.VerifyBytes(s.SignBytes(), s.Sig) {
-		return errors.Unauthorized()
+		return errors.ErrUnauthorized()
 	}
 	return s.Tx.ValidateBasic()
 }
@@ -92,10 +92,10 @@ func (s *OneSig) SignBytes() []byte {
 func (s *OneSig) Sign(pubkey crypto.PubKey, sig crypto.Signature) error {
 	signed := Signed{sig, pubkey}
 	if signed.Empty() {
-		return errors.MissingSignature()
+		return errors.ErrMissingSignature()
 	}
 	if !s.Empty() {
-		return errors.TooManySignatures()
+		return errors.ErrTooManySignatures()
 	}
 	// set the value once we are happy
 	s.Signed = signed
@@ -107,10 +107,10 @@ func (s *OneSig) Sign(pubkey crypto.PubKey, sig crypto.Signature) error {
 // including if there are no signatures
 func (s *OneSig) Signers() ([]crypto.PubKey, error) {
 	if s.Empty() {
-		return nil, errors.MissingSignature()
+		return nil, errors.ErrMissingSignature()
 	}
 	if !s.Pubkey.VerifyBytes(s.SignBytes(), s.Sig) {
-		return nil, errors.InvalidSignature()
+		return nil, errors.ErrInvalidSignature()
 	}
 	return []crypto.PubKey{s.Pubkey}, nil
 }
@@ -168,7 +168,7 @@ func (s *MultiSig) SignBytes() []byte {
 func (s *MultiSig) Sign(pubkey crypto.PubKey, sig crypto.Signature) error {
 	signed := Signed{sig, pubkey}
 	if signed.Empty() {
-		return errors.MissingSignature()
+		return errors.ErrMissingSignature()
 	}
 	// set the value once we are happy
 	s.Sigs = append(s.Sigs, signed)
@@ -180,7 +180,7 @@ func (s *MultiSig) Sign(pubkey crypto.PubKey, sig crypto.Signature) error {
 // including if there are no signatures
 func (s *MultiSig) Signers() ([]crypto.PubKey, error) {
 	if len(s.Sigs) == 0 {
-		return nil, errors.MissingSignature()
+		return nil, errors.ErrMissingSignature()
 	}
 	// verify all the signatures before returning them
 	keys := make([]crypto.PubKey, len(s.Sigs))
@@ -188,7 +188,7 @@ func (s *MultiSig) Signers() ([]crypto.PubKey, error) {
 	for i := range s.Sigs {
 		ms := s.Sigs[i]
 		if !ms.Pubkey.VerifyBytes(data, ms.Sig) {
-			return nil, errors.InvalidSignature()
+			return nil, errors.ErrInvalidSignature()
 		}
 		keys[i] = ms.Pubkey
 	}