diff --git a/src/SerializedObject.h b/src/SerializedObject.h
index 6fd64274cf..776821ac82 100644
--- a/src/SerializedObject.h
+++ b/src/SerializedObject.h
@@ -5,13 +5,17 @@
 
 #include "SerializedTypes.h"
 
+enum SOE_Type
+{
+	SOE_NEVER=-1, SOE_REQUIRED=0, SOE_FLAGS, SOE_IFFLAG=1, SOE_IFNFLAG=2
+};
+
 struct SOElement
 { // An element in the description of a serialized object
 	const char *e_name;
-	int e_flag;
 	SerializedTypeID e_id;
-
-	SOElement(const char *n, int f, SerializedTypeID i) : e_name(n), e_flag(f), e_id(i) { ; }
+	SOE_Type e_type;
+	int e_flags;
 };
 
 struct SOType
diff --git a/src/SerializedTypes.h b/src/SerializedTypes.h
index 81ac8154c7..6c70c9b0a3 100644
--- a/src/SerializedTypes.h
+++ b/src/SerializedTypes.h
@@ -9,9 +9,9 @@
 
 enum SerializedTypeID
 {
-	STI_NOTPRESENT=0, STI_OBJECT=1,
-	STI_UINT8=2, STI_UINT16=3, STI_UINT32=4, STI_UINT64=5,
-	STI_HASH160=6, STI_HASH256=7, STI_VL=8, STI_TL=8
+	STI_DONE=-1, STI_NOTPRESENT=0,
+	STI_OBJECT=1, STI_UINT8=2, STI_UINT16=3, STI_UINT32=4, STI_UINT64=5,
+	STI_HASH160=6, STI_HASH256=7, STI_VL=8, STI_TL=8,
 };
 
 class SerializedType
diff --git a/src/TransactionFormats.h b/src/TransactionFormats.h
new file mode 100644
index 0000000000..3064178ad0
--- /dev/null
+++ b/src/TransactionFormats.h
@@ -0,0 +1,59 @@
+#ifndef __TRANSACTIONFORMATS__
+#define __TRANSACTIONFORMATS__
+
+#include "SerializedObject.h"
+
+#define STI_ACCOUNT STI_HASH160
+
+struct TransactionFormat
+{
+	const char *t_name;
+	int t_id;
+	SOElement elements[16];
+};
+
+TransactionFormat InnerTxnFormats[]=
+{
+	{ "MakePayment", 0, {
+		{ "Flags",        STI_UINT16,  SOE_FLAGS,    0 },
+		{ "Sequence", 	  STI_UINT32,  SOE_REQUIRED, 0 },
+		{ "Destination",  STI_ACCOUNT, SOE_REQUIRED, 0 },
+		{ "Amount",       STI_UINT64,  SOE_REQUIRED, 0 },
+		{ "Currency",     STI_HASH160, SOE_IFFLAG,   1 },
+		{ "SourceTag",    STI_UINT32,  SOE_IFFLAG,   2 },
+		{ "TargetLedger", STI_UINT32,  SOE_IFFLAG,   4 },
+		{ "InvoiceID",    STI_HASH256, SOE_IFFLAG,   8 },
+		{ "Extensions",   STI_TL,      SOE_IFFLAG,   32768 },
+		{ NULL,           STI_DONE,    SOE_NEVER,    -1 } }
+	},
+	{ "Invoice", 1, {
+		{ "Flags",        STI_UINT16,  SOE_FLAGS,    0 },
+		{ "Sequence",     STI_UINT32,  SOE_REQUIRED, 0 },
+		{ "Target",       STI_ACCOUNT, SOE_REQUIRED, 0 },
+		{ "Amount",       STI_UINT64,  SOE_REQUIRED, 0 },
+		{ "Currency",     STI_HASH160, SOE_IFFLAG,   1 },
+		{ "SourceTag",    STI_UINT32,  SOE_IFFLAG,   2 },
+		{ "Destination",  STI_ACCOUNT, SOE_IFFLAG,   4 },
+		{ "TargetLedger", STI_UINT32,  SOE_IFFLAG,   8 },
+		{ "Identifier",   STI_VL,      SOE_IFFLAG,   16 },
+		{ "Extensions",   STI_TL,      SOE_IFFLAG,   32768 },
+		{ NULL,           STI_DONE,    SOE_NEVER,    -1 } }
+	},
+	{ "Offer", 2, {
+		{ "Flags",        STI_UINT16,  SOE_FLAGS,    0 },
+		{ "Sequence",     STI_UINT32,  SOE_REQUIRED, 0 },
+		{ "AmountIn",     STI_UINT64,  SOE_REQUIRED, 0 },
+		{ "CurrencyIn",   STI_HASH160, SOE_IFFLAG,   2 },
+		{ "AmountOut",    STI_UINT64,  SOE_REQUIRED, 0 },
+		{ "CurrencyOut",  STI_HASH160, SOE_IFFLAG,   4 },
+		{ "SourceTag",    STI_UINT32,  SOE_IFFLAG,   8 },
+		{ "Destination",  STI_ACCOUNT, SOE_IFFLAG,   16 },
+		{ "TargetLedger", STI_UINT32,  SOE_IFFLAG,   32 },
+		{ "ExpireLedger", STI_UINT32,  SOE_IFFLAG,   64 },
+		{ "Identifier",   STI_VL,      SOE_IFFLAG,   128 },
+		{ "Extensions",   STI_TL,      SOE_IFFLAG,   32768 },
+		{ NULL,           STI_DONE,    SOE_NEVER,    -1 } }
+	}
+};
+
+#endif