diff --git a/src/NicknameState.cpp b/src/NicknameState.cpp
new file mode 100644
index 0000000000..9b2cb3e857
--- /dev/null
+++ b/src/NicknameState.cpp
@@ -0,0 +1,29 @@
+#include "NicknameState.h"
+
+NicknameState::NicknameState(SerializedLedgerEntry::pointer ledgerEntry) :
+    mLedgerEntry(ledgerEntry)
+{
+    if (!mLedgerEntry || mLedgerEntry->getType() != ltNICKNAME) return;
+}
+
+bool NicknameState::haveMinimumOffer() const
+{
+    return mLedgerEntry->getIFieldPresent(sfMinimumOffer);
+}
+
+STAmount NicknameState::getMinimumOffer() const
+{
+    return mLedgerEntry->getIFieldPresent(sfMinimumOffer)
+	? mLedgerEntry->getIValueFieldAmount(sfMinimumOffer)
+	: STAmount();
+}
+
+NewcoinAddress NicknameState::getAccountID() const
+{
+    return mLedgerEntry->getIValueFieldAccount(sfAccount);
+}
+
+void NicknameState::addJson(Json::Value& val)
+{
+    val = mLedgerEntry->getJson(0);
+}
diff --git a/src/NicknameState.h b/src/NicknameState.h
new file mode 100644
index 0000000000..fe116f4c5d
--- /dev/null
+++ b/src/NicknameState.h
@@ -0,0 +1,37 @@
+#ifndef _NICKNAMESTATE_
+#define _NICKNAMESTATE_
+
+//
+// State of a nickname node.
+// - Isolate ledger entry format.
+//
+
+#include "SerializedLedger.h"
+
+#include <boost/shared_ptr.hpp>
+
+class NicknameState
+{
+public:
+	typedef boost::shared_ptr<NicknameState> pointer;
+
+private:
+	SerializedLedgerEntry::pointer	mLedgerEntry;
+
+public:
+	NicknameState(SerializedLedgerEntry::pointer ledgerEntry);	// For accounts in a ledger
+
+	bool					haveMinimumOffer() const;
+	STAmount				getMinimumOffer() const;
+	NewcoinAddress			getAccountID() const;
+
+	SerializedLedgerEntry::pointer getSLE() { return mLedgerEntry; }
+	const SerializedLedgerEntry& peekSLE() const { return *mLedgerEntry; }
+	SerializedLedgerEntry& peekSLE() { return *mLedgerEntry; }
+
+	std::vector<unsigned char> getRaw() const;
+	void addJson(Json::Value& value);
+};
+
+#endif
+// vim:ts=4
diff --git a/src/RPCServer.cpp b/src/RPCServer.cpp
index 32faabb991..088c8f5c52 100644
--- a/src/RPCServer.cpp
+++ b/src/RPCServer.cpp
@@ -216,7 +216,7 @@ Json::Value RPCServer::getMasterGenerator(const uint256& uLedger, const NewcoinA
 Json::Value RPCServer::authorize(const uint256& uLedger,
 	const NewcoinAddress& naRegularSeed, const NewcoinAddress& naSrcAccountID,
 	NewcoinAddress& naAccountPublic, NewcoinAddress& naAccountPrivate,
-	STAmount& saSrcBalance, uint64 uFee, AccountState::pointer& asSrc,
+	STAmount& saSrcBalance, const STAmount& saFee, AccountState::pointer& asSrc,
 	const NewcoinAddress& naVerifyGenerator)
 {
 	// Source/paying account must exist.
@@ -277,13 +277,13 @@ Json::Value RPCServer::authorize(const uint256& uLedger,
 
 	saSrcBalance	= asSrc->getBalance();
 
-	if (saSrcBalance < uFee)
+	if (saSrcBalance < saFee)
 	{
 		return JSONRPCError(500, "insufficent funds");
 	}
 	else
 	{
-		saSrcBalance -= uFee;
+		saSrcBalance -= saFee;
 	}
 
 	return obj;
@@ -780,7 +780,7 @@ Json::Value RPCServer::doCreditSet(Json::Value& params)
 	}
 	else if (!saLimitAmount.setValue(params[3u].asString(), params.size() >= 5 ? params[4u].asString() : ""))
 	{
-		return JSONRPCError(500, "bad src amount/currency");
+		return JSONRPCError(400, "bad src amount/currency");
 	}
 	else if (!mNetOps->available())
 	{
@@ -828,6 +828,7 @@ Json::Value RPCServer::doCreditSet(Json::Value& params)
 }
 
 // nickname_info <nickname>
+// Note: Nicknames are not automatically looked up by commands as they are advisory and can be changed.
 Json::Value RPCServer::doNicknameInfo(Json::Value& params)
 {
 	uint256			uLedger;
@@ -871,20 +872,38 @@ Json::Value RPCServer::doNicknameInfo(Json::Value& params)
 // nickname_set <seed> <paying_account> <nickname> [<offer_minimum>] [<authorization>]
 Json::Value RPCServer::doNicknameSet(Json::Value& params)
 {
+	NewcoinAddress	naSrcAccountID;
+	NewcoinAddress	naSeed;
 	uint256			uLedger;
 
 	if (params.size() < 2 || params.size() > 3)
 	{
 		return JSONRPCError(400, "invalid params");
 	}
+	else if (!naSeed.setFamilySeedGeneric(params[0u].asString()))
+	{
+		return "disallowed seed";
+	}
+	else if (!naSrcAccountID.setAccountID(params[1u].asString()))
+	{
+		return "bad source account id needed";
+	}
 
-	std::string	strNickname	= params[2u].asString();
-		boost::trim(strNickname);
+	STAmount					saMinimumOffer;
+	bool						bSetOffer		= params.size() >= 4;
+	std::string					strOfferCurrency;
+	std::string					strNickname		= params[2u].asString();
+									boost::trim(strNickname);
+	std::vector<unsigned char>	vucSignature;
 
 	if (strNickname.empty())
 	{
 		return JSONRPCError(400, "invalid nickname (zero length)");
 	}
+	else if (params.size() >= 4 && !saMinimumOffer.setValue(params[3u].asString(), strOfferCurrency))
+	{
+		return JSONRPCError(400, "bad dst amount/currency");
+	}
 	else if (!mNetOps->available())
 	{
 		return JSONRPCError(503, "network not available");
@@ -894,9 +913,56 @@ Json::Value RPCServer::doNicknameSet(Json::Value& params)
 		return JSONRPCError(503, "no current ledger");
 	}
 
+	STAmount				saFee;
 	NicknameState::pointer	nsSrc	= mNetOps->getNicknameState(uLedger, strNickname);
 
-	return "not implemented";
+	if (!nsSrc)
+	{
+		// Creating nickname.
+		saFee	= theConfig.FEE_NICKNAME_CREATE;
+	}
+	else if (naSrcAccountID != nsSrc->getAccountID())
+	{
+		// We don't own the nickname.
+		return JSONRPCError(400, "account does not control nickname");
+	}
+	else
+	{
+		// Setting the minimum offer.
+		saFee	= theConfig.FEE_DEFAULT;
+	}
+
+	NewcoinAddress			naMasterGenerator;
+	NewcoinAddress			naAccountPublic;
+	NewcoinAddress			naAccountPrivate;
+	AccountState::pointer	asSrc;
+	STAmount				saSrcBalance;
+	Json::Value				obj				= authorize(uLedger, naSeed, naSrcAccountID, naAccountPublic, naAccountPrivate,
+		saSrcBalance, saFee, asSrc, naMasterGenerator);
+
+	if (!obj.empty())
+		return obj;
+
+	// YYY Could verify nickname does not exist or points to paying account.
+	// XXX Adjust fee for nickname create.
+
+	Transaction::pointer	trans	= Transaction::sharedNicknameSet(
+		naAccountPublic, naAccountPrivate,
+		naSrcAccountID,
+		asSrc->getSeq(),
+		saFee,
+		0,											// YYY No source tag
+		Ledger::getNicknameHash(strNickname),
+		bSetOffer,
+		saMinimumOffer,
+		vucSignature);
+
+	(void) mNetOps->processTransaction(trans);
+
+	obj["transaction"]	= trans->getSTransaction()->getJson(0);
+	obj["status"]		= trans->getStatus();
+
+	return obj;
 }
 
 // password_fund <seed> <paying_account> [<account>]
@@ -1106,11 +1172,11 @@ Json::Value RPCServer::doSend(Json::Value& params)
 	}
 	else if (!saDstAmount.setValue(params[3u].asString(), sDstCurrency))
 	{
-		return JSONRPCError(500, "bad dst amount/currency");
+		return JSONRPCError(400, "bad dst amount/currency");
 	}
 	else if (params.size() >= 6 && !saSrcAmount.setValue(params[5u].asString(), sSrcCurrency))
 	{
-		return JSONRPCError(500, "bad src amount/currency");
+		return JSONRPCError(400, "bad src amount/currency");
 	}
 	else if (!mNetOps->available())
 	{
@@ -1474,7 +1540,7 @@ Json::Value RPCServer::doWalletAdd(Json::Value& params)
 	}
 	else if (params.size() >= 4 && !saAmount.setValue(params[3u].asString(), sDstCurrency))
 	{
-		return JSONRPCError(500, "bad dst amount/currency");
+		return JSONRPCError(400, "bad dst amount/currency");
 	}
 	else if (!mNetOps->available())
 	{
@@ -1497,7 +1563,7 @@ Json::Value RPCServer::doWalletAdd(Json::Value& params)
 	    AccountState::pointer	asSrc;
 		STAmount				saSrcBalance;
 		Json::Value				obj			= authorize(uLedger, naRegularSeed, naSrcAccountID, naAccountPublic, naAccountPrivate,
-			saSrcBalance, theConfig.FEE_CREATE, asSrc, naMasterGenerator);
+			saSrcBalance, theConfig.FEE_ACCOUNT_CREATE, asSrc, naMasterGenerator);
 
 		if (!obj.empty())
 			return obj;
@@ -1544,7 +1610,7 @@ Json::Value RPCServer::doWalletAdd(Json::Value& params)
 				naAccountPublic, naAccountPrivate,
 				naSrcAccountID,
 				asSrc->getSeq(),
-				theConfig.FEE_CREATE,
+				theConfig.FEE_ACCOUNT_CREATE,
 				0,											// YYY No source tag
 				saAmount,
 				naAuthKeyID,
@@ -1705,7 +1771,7 @@ Json::Value RPCServer::doWalletCreate(Json::Value& params)
 	AccountState::pointer	asSrc;
 	STAmount				saSrcBalance;
 	Json::Value				obj				= authorize(uLedger, naSeed, naSrcAccountID, naAccountPublic, naAccountPrivate,
-		saSrcBalance, theConfig.FEE_CREATE, asSrc, naMasterGenerator);
+		saSrcBalance, theConfig.FEE_ACCOUNT_CREATE, asSrc, naMasterGenerator);
 
 	if (!obj.empty())
 		return obj;
@@ -1719,7 +1785,7 @@ Json::Value RPCServer::doWalletCreate(Json::Value& params)
 		naAccountPublic, naAccountPrivate,
 		naSrcAccountID,
 		asSrc->getSeq(),
-		theConfig.FEE_CREATE,
+		theConfig.FEE_ACCOUNT_CREATE,
 		0,											// YYY No source tag
 		naDstAccountID,
 		saInitialFunds);							// Initial funds in XNC.
diff --git a/src/RPCServer.h b/src/RPCServer.h
index a8358235c3..a972b05a6e 100644
--- a/src/RPCServer.h
+++ b/src/RPCServer.h
@@ -42,7 +42,7 @@ private:
 	Json::Value getMasterGenerator(const uint256& uLedger, const NewcoinAddress& naRegularSeed, NewcoinAddress& naMasterGenerator);
 	Json::Value authorize(const uint256& uLedger, const NewcoinAddress& naRegularSeed, const NewcoinAddress& naSrcAccountID,
 	    NewcoinAddress& naAccountPublic, NewcoinAddress& naAccountPrivate,
-		STAmount& saSrcBalance, uint64 uFee, AccountState::pointer& asSrc,
+		STAmount& saSrcBalance, const STAmount& saFee, AccountState::pointer& asSrc,
 		const NewcoinAddress& naVerifyGenerator);
 	Json::Value accounts(const uint256& uLedger, const NewcoinAddress& naMasterGenerator);