diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index daf35988..b4b0299d 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -49,10 +49,10 @@ int64 AmountFromValue(const Value& value)
 {
     double dAmount = value.get_real();
     if (dAmount <= 0.0 || dAmount > MAX_MONEY)
-        throw JSONRPCError(-3, "Invalid amount");
+        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount");
     int64 nAmount = roundint64(dAmount * COIN);
     if (!MoneyRange(nAmount))
-        throw JSONRPCError(-3, "Invalid amount");
+        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount");
     return nAmount;
 }
 
@@ -288,13 +288,15 @@ Value getwork(const Array& params, bool fHelp)
             "If [data] is specified, tries to solve the block and returns true if it was successful.");
 
     if (vNodes.empty())
-        throw JSONRPCError(-9, "Paycoin is not connected!");
+        throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Paycoin is not connected!");
 
     if (IsInitialBlockDownload())
-        throw JSONRPCError(-10, "Paycoin is downloading blocks...");
+        throw JSONRPCError(RPC_CLIENT_IN_INITIAL_DOWNLOAD, "Paycoin is downloading blocks...");
 
     if (pindexBest != NULL && pindexBest->nTime > POW_END_TIME)
-        throw JSONRPCError(-10, "Paycoin is currently on pure PoS state");
+        /* This was set to -10 but really this seems inappropriate, unsure what
+         * to set to instead. */
+        throw JSONRPCError(RPC_CLIENT_IN_INITIAL_DOWNLOAD, "Paycoin is currently on pure PoS state");
 
 
     typedef map<uint256, pair<CBlock*, CScript> > mapNewBlock_t;
@@ -331,7 +333,7 @@ Value getwork(const Array& params, bool fHelp)
             // Create new block
             pblock = CreateNewBlock(*pMiningKey, pwalletMain);
             if (!pblock)
-                throw JSONRPCError(-7, "Out of memory");
+                throw JSONRPCError(RPC_OUT_OF_MEMORY, "Out of memory");
             vNewBlock.push_back(pblock);
 
             // Need to update only after we know CreateNewBlock succeeded
@@ -369,7 +371,7 @@ Value getwork(const Array& params, bool fHelp)
         // Parse parameters
         vector<unsigned char> vchData = ParseHex(params[0].get_str());
         if (vchData.size() != 128)
-            throw JSONRPCError(-8, "Invalid parameter");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter");
         CBlock* pdata = (CBlock*)&vchData[0];
 
         // Byte reverse
@@ -388,6 +390,7 @@ Value getwork(const Array& params, bool fHelp)
 
         assert(pwalletMain != NULL);
         if (!pblock->SignBlock(*pwalletMain))
+            // Should this be a defined error, if so what?
             throw JSONRPCError(-100, "Unable to sign block, wallet locked?");
 
         return CheckWork(pblock, *pwalletMain, *pMiningKey);
@@ -428,21 +431,22 @@ Value getblocktemplate(const Array& params, bool fHelp)
             /* Do nothing */
         }
         else
-            throw JSONRPCError(-8, "Invalid mode");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid mode");
     }
 
     if (strMode != "template")
-        throw JSONRPCError(-8, "Invalid mode");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid mode");
 
     {
         if (vNodes.empty())
-            throw JSONRPCError(-9, "Paycoin is not connected!");
+            throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Paycoin is not connected!");
 
         if (IsInitialBlockDownload())
-            throw JSONRPCError(-10, "Paycoin is downloading blocks...");
+            throw JSONRPCError(RPC_CLIENT_IN_INITIAL_DOWNLOAD, "Paycoin is downloading blocks...");
 
         if (pindexBest != NULL && pindexBest->nTime > POW_END_TIME)
-            throw JSONRPCError(-10, "Paycoin is currently on pure PoS state");
+            // Same as other instance, this feels like the wrong error code for this...
+            throw JSONRPCError(RPC_CLIENT_IN_INITIAL_DOWNLOAD, "Paycoin is currently on pure PoS state");
 
         // Update block
         static unsigned int nTransactionsUpdatedLast;
@@ -468,7 +472,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
             }
             pblock = CreateNewBlock(*pMiningKey, pwalletMain);
             if (!pblock)
-                throw JSONRPCError(-7, "Out of memory");
+                throw JSONRPCError(RPC_OUT_OF_MEMORY, "Out of memory");
 
             // Need to update only after we know CreateNewBlock succeeded
             pindexPrev = pindexPrevNew;
@@ -570,11 +574,12 @@ Value submitblock(const Array& params, bool fHelp)
         ssBlock >> block;
     }
     catch (std::exception &e) {
-        throw JSONRPCError(-22, "Block decode failed");
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "Block decode failed");
     }
 
     // Paycoin: sign block
     if (!block.SignBlock(*pwalletMain))
+        // Once again, should this be a defined error and if so what?
         throw JSONRPCError(-100, "Unable to sign block, wallet locked?");
 
     bool fAccepted = CheckWork(&block, *pwalletMain, *pMiningKey);
@@ -827,7 +832,7 @@ string rfc1123Time()
 
 static string HTTPReply(int nStatus, const string& strMsg)
 {
-    if (nStatus == 401)
+    if (nStatus == HTTP_UNAUTHORIZED)
         return strprintf("HTTP/1.0 401 Authorization Required\r\n"
             "Date: %s\r\n"
             "Server: paycoin-json-rpc/%s\r\n"
@@ -845,11 +850,11 @@ static string HTTPReply(int nStatus, const string& strMsg)
             "<BODY><H1>401 Unauthorized.</H1></BODY>\r\n"
             "</HTML>\r\n", rfc1123Time().c_str(), FormatFullVersion().c_str());
     const char *cStatus;
-         if (nStatus == 200) cStatus = "OK";
-    else if (nStatus == 400) cStatus = "Bad Request";
-    else if (nStatus == 403) cStatus = "Forbidden";
-    else if (nStatus == 404) cStatus = "Not Found";
-    else if (nStatus == 500) cStatus = "Internal Server Error";
+         if (nStatus == HTTP_OK) cStatus = "OK";
+    else if (nStatus == HTTP_BAD_REQUEST) cStatus = "Bad Request";
+    else if (nStatus == HTTP_FORBIDDEN) cStatus = "Forbidden";
+    else if (nStatus == HTTP_NOT_FOUND) cStatus = "Not Found";
+    else if (nStatus == HTTP_INTERNAL_SERVER_ERROR) cStatus = "Internal Server Error";
     else cStatus = "";
     return strprintf(
             "HTTP/1.1 %d %s\r\n"
@@ -875,7 +880,7 @@ int ReadHTTPStatus(std::basic_istream<char>& stream)
     vector<string> vWords;
     boost::split(vWords, str, boost::is_any_of(" "));
     if (vWords.size() < 2)
-        return 500;
+        return HTTP_INTERNAL_SERVER_ERROR;
     return atoi(vWords[1].c_str());
 }
 
@@ -915,7 +920,7 @@ int ReadHTTP(std::basic_istream<char>& stream, map<string, string>& mapHeadersRe
     // Read header
     int nLen = ReadHTTPHeader(stream, mapHeadersRet);
     if (nLen < 0 || nLen > (int)MAX_SIZE)
-        return 500;
+        return HTTP_INTERNAL_SERVER_ERROR;
 
     // Read message
     if (nLen > 0)
@@ -978,10 +983,10 @@ string JSONRPCReply(const Value& result, const Value& error, const Value& id)
 void ErrorReply(std::ostream& stream, const Object& objError, const Value& id)
 {
     // Send error reply from json-rpc error object
-    int nStatus = 500;
+    int nStatus = HTTP_INTERNAL_SERVER_ERROR;
     int code = find_value(objError, "code").get_int();
-    if (code == -32600) nStatus = 400;
-    else if (code == -32601) nStatus = 404;
+    if (code == RPC_INVALID_REQUEST) nStatus = HTTP_BAD_REQUEST;
+    else if (code == RPC_METHOD_NOT_FOUND) nStatus = HTTP_NOT_FOUND;
     string strReply = JSONRPCReply(Value::null, objError, id);
     stream << HTTPReply(nStatus, strReply) << std::flush;
 }
@@ -1085,9 +1090,9 @@ static Object JSONRPCExecOne(const Value& request)
         // Parse method
         Value valMethod = find_value(req, "method");
         if (valMethod.type() == null_type)
-            throw JSONRPCError(-32600, "Missing method");
+            throw JSONRPCError(RPC_INVALID_REQUEST, "Missing method");
         if (valMethod.type() != str_type)
-            throw JSONRPCError(-32600, "Method must be a string");
+            throw JSONRPCError(RPC_INVALID_REQUEST, "Method must be a string");
         string strMethod = valMethod.get_str();
         if (strMethod != "getwork" && strMethod != "getblocktemplate")
             printf("ThreadRPCServer method=%s\n", strMethod.c_str());
@@ -1100,7 +1105,7 @@ static Object JSONRPCExecOne(const Value& request)
         else if (valParams.type() == null_type)
             params = Array();
         else
-            throw JSONRPCError(-32600, "Params must be an array");
+            throw JSONRPCError(RPC_INVALID_PARAMS, "Params must be an array");
 
         Value result = tableRPC.execute(strMethod, params);
         rpc_result = JSONRPCReplyObj(result, Value::null, id);
@@ -1111,7 +1116,7 @@ static Object JSONRPCExecOne(const Value& request)
     }
     catch (std::exception& e)
     {
-        rpc_result = JSONRPCReplyObj(Value::null, JSONRPCError(-32700, e.what()), id);
+        rpc_result = JSONRPCReplyObj(Value::null, JSONRPCError(RPC_PARSE_ERROR, e.what()), id);
     }
 
     return rpc_result;
@@ -1216,7 +1221,7 @@ void ThreadRPCServer2(void* parg)
         {
             // Only send a 403 if we're not using SSL to prevent a DoS during the SSL handshake.
             if (!fUseSSL)
-                stream << HTTPReply(403, "") << std::flush;
+                stream << HTTPReply(HTTP_FORBIDDEN, "") << std::flush;
             continue;
         }
 
@@ -1234,7 +1239,7 @@ void ThreadRPCServer2(void* parg)
         // Check authorization
         if (mapHeaders.count("authorization") == 0)
         {
-            stream << HTTPReply(401, "") << std::flush;
+            stream << HTTPReply(HTTP_UNAUTHORIZED, "") << std::flush;
             continue;
         }
         if (!HTTPAuthorized(mapHeaders))
@@ -1246,7 +1251,7 @@ void ThreadRPCServer2(void* parg)
             if (mapArgs["-rpcpassword"].size() < 20)
                 Sleep(250);
 
-            stream << HTTPReply(401, "") << std::flush;
+            stream << HTTPReply(HTTP_UNAUTHORIZED, "") << std::flush;
             continue;
         }
 
@@ -1256,7 +1261,7 @@ void ThreadRPCServer2(void* parg)
             // Parse request
             Value valRequest;
             if (!read_string(strRequest, valRequest))
-                throw JSONRPCError(-32700, "Parse error");
+                throw JSONRPCError(RPC_PARSE_ERROR, "Parse error");
 
             string strReply;
             if (valRequest.type() == obj_type) {
@@ -1268,10 +1273,10 @@ void ThreadRPCServer2(void* parg)
               // array of requests
               strReply = JSONRPCExecBatch(valRequest.get_array());
             } else
-              throw JSONRPCError(-32600, "Top-level object parse error");
+              throw JSONRPCError(RPC_INVALID_REQUEST, "Top-level object parse error");
 
             // Send reply
-            stream << HTTPReply(200, strReply) << std::flush;
+            stream << HTTPReply(HTTP_OK, strReply) << std::flush;
         }
         catch (Object& objError)
         {
@@ -1279,7 +1284,7 @@ void ThreadRPCServer2(void* parg)
         }
         catch (std::exception& e)
         {
-            ErrorReply(stream, JSONRPCError(-32700, e.what()), id);
+            ErrorReply(stream, JSONRPCError(RPC_PARSE_ERROR, e.what()), id);
         }
     }
 }
@@ -1289,13 +1294,13 @@ json_spirit::Value CRPCTable::execute(const std::string &strMethod, const json_s
     // Find method
     const CRPCCommand *pcmd = tableRPC[strMethod];
     if (!pcmd)
-        throw JSONRPCError(-32601, "Method not found");
+        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Method not found");
 
     // Observe safe mode
     string strWarning = GetWarnings("rpc");
     if (strWarning != "" && !GetBoolArg("-disablesafemode") &&
         !pcmd->okSafeMode)
-        throw JSONRPCError(-2, string("Safe mode: ") + strWarning);
+        throw JSONRPCError(RPC_FORBIDDEN_BY_SAFE_MODE, string("Safe mode: ") + strWarning);
 
     try
     {
@@ -1309,7 +1314,7 @@ json_spirit::Value CRPCTable::execute(const std::string &strMethod, const json_s
     }
     catch (std::exception& e)
     {
-        throw JSONRPCError(-1, e.what());
+        throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }
 }
 
@@ -1331,7 +1336,7 @@ Object CallRPC(const string& strMethod, const Array& params)
     SSLIOStreamDevice d(sslStream, fUseSSL);
     iostreams::stream<SSLIOStreamDevice> stream(d);
     if (!d.connect(GetArg("-rpcconnect", "127.0.0.1"), GetArg("-rpcport", CBigNum(fTestNet? TESTNET_RPC_PORT : RPC_PORT).ToString().c_str())))
-        throw runtime_error("couldn't connect to server");
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "couldn't connect to server");
 
     // HTTP basic authentication
     string strUserPass64 = EncodeBase64(mapArgs["-rpcuser"] + ":" + mapArgs["-rpcpassword"]);
@@ -1347,20 +1352,20 @@ Object CallRPC(const string& strMethod, const Array& params)
     map<string, string> mapHeaders;
     string strReply;
     int nStatus = ReadHTTP(stream, mapHeaders, strReply);
-    if (nStatus == 401)
-        throw runtime_error("incorrect rpcuser or rpcpassword (authorization failed)");
-    else if (nStatus >= 400 && nStatus != 400 && nStatus != 404 && nStatus != 500)
-        throw runtime_error(strprintf("server returned HTTP error %d", nStatus));
+    if (nStatus == HTTP_UNAUTHORIZED)
+        throw JSONRPCError(RPC_INVALID_PARAMS, "incorrect rpcuser or rpcpassword (authorization failed)");
+    else if (nStatus >= HTTP_BAD_REQUEST && nStatus != HTTP_BAD_REQUEST && nStatus != HTTP_NOT_FOUND && nStatus != HTTP_INTERNAL_SERVER_ERROR)
+        throw JSONRPCError(RPC_INTERNAL_ERROR, strprintf("server returned HTTP error %d", nStatus));
     else if (strReply.empty())
-        throw runtime_error("no response from server");
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "no response from server");
 
     // Parse reply
     Value valReply;
     if (!read_string(strReply, valReply))
-        throw runtime_error("couldn't parse reply from server");
+        throw JSONRPCError(RPC_PARSE_ERROR, "couldn't parse reply from server");
     const Object& reply = valReply.get_obj();
     if (reply.empty())
-        throw runtime_error("expected reply to have result, error and id properties");
+        throw JSONRPCError(RPC_PARSE_ERROR, "expected reply to have result, error and id properties");
 
     return reply;
 }
@@ -1372,7 +1377,7 @@ template<typename T> void ConvertTo(Value& value)
         // reinterpret string as unquoted json value
         Value value2;
         if (!read_string(value.get_str(), value2))
-            throw runtime_error("type mismatch");
+            throw JSONRPCError(RPC_PARSE_ERROR, "type mismatch");
         value = value2.get_value<T>();
     }
     else
@@ -1430,7 +1435,7 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
         string s = params[1].get_str();
         Value v;
         if (!read_string(s, v) || v.type() != obj_type)
-            throw runtime_error("type mismatch");
+            throw JSONRPCError(RPC_PARSE_ERROR, "type mismatch");
         params[1] = v.get_obj();
     }
     if (strMethod == "sendmany"                && n > 2) ConvertTo<boost::int64_t>(params[2]);
@@ -1442,7 +1447,7 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
         string s = params[1].get_str();
         Value v;
         if (!read_string(s, v) || v.type() != array_type)
-            throw runtime_error("type mismatch "+s);
+            throw JSONRPCError(RPC_PARSE_ERROR, "type mismatch "+s);
         params[1] = v.get_array();
     }
     if (strMethod == "addmultisigaddress"      && n > 0) ConvertTo<boost::int64_t>(params[0]);
@@ -1451,7 +1456,7 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
         string s = params[1].get_str();
         Value v;
         if (!read_string(s, v) || v.type() != array_type)
-            throw runtime_error("type mismatch "+s);
+            throw JSONRPCError(RPC_PARSE_ERROR, "type mismatch "+s);
         params[1] = v.get_array();
     }
     if (strMethod == "listunspent"            && n > 0) ConvertTo<boost::int64_t>(params[0]);
@@ -1485,7 +1490,7 @@ int CommandLineRPC(int argc, char *argv[])
 
         // Method
         if (argc < 2)
-            throw runtime_error("too few parameters");
+            throw JSONRPCError(RPC_INVALID_PARAMS, "too few parameters");
         string strMethod = argv[1];
 
         // Parameters default to strings
diff --git a/src/bitcoinrpc.h b/src/bitcoinrpc.h
index bf0a0d4b..fc87a43f 100644
--- a/src/bitcoinrpc.h
+++ b/src/bitcoinrpc.h
@@ -17,6 +17,68 @@ class CReserveKey;
 #include "json/json_spirit_writer_template.h"
 #include "json/json_spirit_utils.h"
 
+//! HTTP status codes
+enum HTTPStatusCode
+{
+    HTTP_OK                    = 200,
+    HTTP_BAD_REQUEST           = 400,
+    HTTP_UNAUTHORIZED          = 401,
+    HTTP_FORBIDDEN             = 403,
+    HTTP_NOT_FOUND             = 404,
+    HTTP_BAD_METHOD            = 405,
+    HTTP_INTERNAL_SERVER_ERROR = 500,
+    HTTP_SERVICE_UNAVAILABLE   = 503,
+};
+
+//! Bitcoin RPC error codes
+enum RPCErrorCode
+{
+    //! Standard JSON-RPC 2.0 errors
+    RPC_INVALID_REQUEST  = -32600,
+    RPC_METHOD_NOT_FOUND = -32601,
+    RPC_INVALID_PARAMS   = -32602,
+    RPC_INTERNAL_ERROR   = -32603,
+    RPC_PARSE_ERROR      = -32700,
+
+    //! General application defined errors
+    RPC_MISC_ERROR                  = -1,  //! std::exception thrown in command handling
+    RPC_FORBIDDEN_BY_SAFE_MODE      = -2,  //! Server is in safe mode, and command is not allowed in safe mode
+    RPC_TYPE_ERROR                  = -3,  //! Unexpected type was passed as parameter
+    RPC_INVALID_ADDRESS_OR_KEY      = -5,  //! Invalid address or key
+    RPC_OUT_OF_MEMORY               = -7,  //! Ran out of memory during operation
+    RPC_INVALID_PARAMETER           = -8,  //! Invalid, missing or duplicate parameter
+    RPC_DATABASE_ERROR              = -20, //! Database error
+    RPC_DESERIALIZATION_ERROR       = -22, //! Error parsing or validating structure in raw format
+    RPC_VERIFY_ERROR                = -25, //! General error during transaction or block submission
+    RPC_VERIFY_REJECTED             = -26, //! Transaction or block was rejected by network rules
+    RPC_VERIFY_ALREADY_IN_CHAIN     = -27, //! Transaction already in chain
+    RPC_IN_WARMUP                   = -28, //! Client still warming up
+
+    //! Aliases for backward compatibility
+    RPC_TRANSACTION_ERROR           = RPC_VERIFY_ERROR,
+    RPC_TRANSACTION_REJECTED        = RPC_VERIFY_REJECTED,
+    RPC_TRANSACTION_ALREADY_IN_CHAIN= RPC_VERIFY_ALREADY_IN_CHAIN,
+
+    //! P2P client errors
+    RPC_CLIENT_NOT_CONNECTED        = -9,  //! Bitcoin is not connected
+    RPC_CLIENT_IN_INITIAL_DOWNLOAD  = -10, //! Still downloading initial blocks
+    RPC_CLIENT_NODE_ALREADY_ADDED   = -23, //! Node is already added
+    RPC_CLIENT_NODE_NOT_ADDED       = -24, //! Node has not been added before
+    RPC_CLIENT_NODE_NOT_CONNECTED   = -29, //! Node to disconnect not found in connected nodes
+    RPC_CLIENT_INVALID_IP_OR_SUBNET = -30, //! Invalid IP/Subnet
+
+    //! Wallet errors
+    RPC_WALLET_ERROR                = -4,  //! Unspecified problem with wallet (key not found etc.)
+    RPC_WALLET_INSUFFICIENT_FUNDS   = -6,  //! Not enough funds in wallet or account
+    RPC_WALLET_INVALID_ACCOUNT_NAME = -11, //! Invalid account name
+    RPC_WALLET_KEYPOOL_RAN_OUT      = -12, //! Keypool ran out, call keypoolrefill first
+    RPC_WALLET_UNLOCK_NEEDED        = -13, //! Enter the wallet passphrase with walletpassphrase first
+    RPC_WALLET_PASSPHRASE_INCORRECT = -14, //! The wallet passphrase entered was incorrect
+    RPC_WALLET_WRONG_ENC_STATE      = -15, //! Command given in wrong wallet encryption state (encrypting an encrypted wallet etc.)
+    RPC_WALLET_ENCRYPTION_FAILED    = -16, //! Failed to encrypt the wallet
+    RPC_WALLET_ALREADY_UNLOCKED     = -17, //! Wallet is already unlocked
+};
+
 void ThreadRPCServer(void* parg);
 int CommandLineRPC(int argc, char *argv[]);
 
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index aeaaf03a..6c7af115 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -137,7 +137,7 @@ Value getblockhash(const Array& params, bool fHelp)
 
     int nHeight = params[0].get_int();
     if (nHeight < 0 || nHeight > nBestHeight)
-        throw runtime_error("Block number out of range.");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Block number out of range.");
 
     CBlockIndex* pblockindex = FindBlockByHeight(nHeight);
     return pblockindex->phashBlock->GetHex();
@@ -156,7 +156,7 @@ Value getblock(const Array& params, bool fHelp)
     uint256 hash(strHash);
 
     if (mapBlockIndex.count(hash) == 0)
-        throw JSONRPCError(-5, "Block not found");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Block not found");
 
     CBlock block;
     CBlockIndex* pblockindex = mapBlockIndex[hash];
diff --git a/src/rpcdump.cpp b/src/rpcdump.cpp
index 3acdb00d..b65ff879 100644
--- a/src/rpcdump.cpp
+++ b/src/rpcdump.cpp
@@ -20,8 +20,6 @@
 using namespace json_spirit;
 using namespace std;
 
-extern Object JSONRPCError(int code, const string& message);
-
 class CTxDump
 {
 public:
@@ -54,11 +52,11 @@ Value importprivkey(const Array& params, bool fHelp)
     CBitcoinSecret vchSecret;
     bool fGood = vchSecret.SetString(strSecret);
 
-    if (!fGood) throw JSONRPCError(-5,"Invalid private key");
+    if (!fGood) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,"Invalid private key");
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
     if (fWalletUnlockMintOnly) // paycoin: no importprivkey in mint-only mode
-        throw JSONRPCError(-102, "Wallet is unlocked for minting only (unlock with walletpassphrase).");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Wallet is unlocked for minting only (unlock with walletpassphrase).");
 
     CKey key;
     bool fCompressed;
@@ -72,7 +70,7 @@ Value importprivkey(const Array& params, bool fHelp)
         pwalletMain->SetAddressBookName(vchAddress, strLabel);
 
         if (!pwalletMain->AddKey(key))
-            throw JSONRPCError(-4,"Error adding key to wallet");
+            throw JSONRPCError(RPC_WALLET_ERROR, "Error adding key to wallet");
 
         pwalletMain->ScanForWalletTransactions(pindexGenesisBlock, true);
         pwalletMain->ReacceptWalletTransactions();
@@ -93,17 +91,17 @@ Value dumpprivkey(const Array& params, bool fHelp)
     string strAddress = params[0].get_str();
     CBitcoinAddress address;
     if (!address.SetString(strAddress))
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
     if (fWalletUnlockMintOnly) // paycoin: no dumpprivkey in mint-only mode
-        throw JSONRPCError(-102, "Wallet is unlocked for minting only (unlock with walletpassphrase).");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Wallet is unlocked for minting only (unlock with walletpassphrase).");
     CKeyID keyID;
     if (!address.GetKeyID(keyID))
-        throw JSONRPCError(-3, "Address does not refer to a key");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Address does not refer to a key");
     CSecret vchSecret;
     bool fCompressed;
     if (!pwalletMain->GetSecret(keyID, vchSecret, fCompressed))
-        throw JSONRPCError(-4,"Private key for address " + strAddress + " is not known");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Private key for address " + strAddress + " is not known");
     return CBitcoinSecret(vchSecret, fCompressed).ToString();
 }
diff --git a/src/rpcnet.cpp b/src/rpcnet.cpp
index 0ddcd2cc..353e9530 100644
--- a/src/rpcnet.cpp
+++ b/src/rpcnet.cpp
@@ -108,11 +108,9 @@ Value sendalert(const Array& params, bool fHelp)
     vector<unsigned char> vchPrivKey = ParseHex(params[1].get_str());
     key.SetPrivKey(CPrivKey(vchPrivKey.begin(), vchPrivKey.end())); // if key is not correct openssl may crash
     if (!key.Sign(Hash(alert.vchMsg.begin(), alert.vchMsg.end()), alert.vchSig))
-        throw runtime_error(
-            "Unable to sign alert, check private key?\n");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Unable to sign alert, check private key?\n");
     if(!alert.ProcessAlert())
-        throw runtime_error(
-            "Failed to process alert.\n");
+        throw JSONRPCError(RPC_MISC_ERROR, "Failed to process alert.\n");
     // Relay alert
     {
         LOCK(cs_vNodes);
diff --git a/src/rpcrawtransaction.cpp b/src/rpcrawtransaction.cpp
index c1904ce8..646e72c3 100644
--- a/src/rpcrawtransaction.cpp
+++ b/src/rpcrawtransaction.cpp
@@ -190,7 +190,7 @@ Value getrawtransaction(const Array& params, bool fHelp)
     CTransaction tx;
     uint256 hashBlock = 0;
     if (!GetTransaction(hash, tx, hashBlock))
-        throw JSONRPCError(-5, "No information available about transaction");
+        throw JSONRPCError(RPC_WALLET_ERROR, "No information available about transaction");
 
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << tx;
@@ -232,9 +232,9 @@ Value listunspent(const Array& params, bool fHelp)
         {
             CBitcoinAddress address(input.get_str());
             if (!address.IsValid())
-                throw JSONRPCError(-5, string("Invalid Bitcoin address: ")+input.get_str());
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid Paycoin address: ")+input.get_str());
             if (setAddress.count(address))
-                throw JSONRPCError(-8, string("Invalid parameter, duplicated address: ")+input.get_str());
+                throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid parameter, duplicated address: ")+input.get_str());
            setAddress.insert(address);
         }
     }
@@ -301,17 +301,17 @@ Value createrawtransaction(const Array& params, bool fHelp)
 
         const Value& txid_v = find_value(o, "txid");
         if (txid_v.type() != str_type)
-            throw JSONRPCError(-8, "Invalid parameter, missing txid key");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, missing txid key");
         string txid = txid_v.get_str();
         if (!IsHex(txid))
-            throw JSONRPCError(-8, "Invalid parameter, expected hex txid");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, expected hex txid");
 
         const Value& vout_v = find_value(o, "vout");
         if (vout_v.type() != int_type)
-            throw JSONRPCError(-8, "Invalid parameter, missing vout key");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, missing vout key");
         int nOutput = vout_v.get_int();
         if (nOutput < 0)
-            throw JSONRPCError(-8, "Invalid parameter, vout must be positive");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout must be positive");
 
         CTxIn in(COutPoint(uint256(txid), nOutput));
         rawTx.vin.push_back(in);
@@ -322,10 +322,10 @@ Value createrawtransaction(const Array& params, bool fHelp)
     {
         CBitcoinAddress address(s.name_);
         if (!address.IsValid())
-            throw JSONRPCError(-5, string("Invalid Bitcoin address: ")+s.name_);
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid Paycoin address: ")+s.name_);
 
         if (setAddress.count(address))
-            throw JSONRPCError(-8, string("Invalid parameter, duplicated address: ")+s.name_);
+            throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid parameter, duplicated address: ")+s.name_);
         setAddress.insert(address);
 
         CScript scriptPubKey;
@@ -355,7 +355,7 @@ Value decoderawtransaction(const Array& params, bool fHelp)
         ssData >> tx;
     }
     catch (std::exception &e) {
-        throw JSONRPCError(-22, "TX decode failed");
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
     }
 
     Object result;
@@ -391,12 +391,12 @@ Value signrawtransaction(const Array& params, bool fHelp)
             txVariants.push_back(tx);
         }
         catch (std::exception &e) {
-            throw JSONRPCError(-22, "TX decode failed");
+            throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
         }
     }
 
     if (txVariants.empty())
-        throw JSONRPCError(-22, "Missing transaction");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Missing transaction");
 
     // mergedTx will end up with all the signatures; it
     // starts as a clone of the rawtx:
@@ -437,7 +437,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
             CBitcoinSecret vchSecret;
             bool fGood = vchSecret.SetString(k.get_str());
             if (!fGood)
-                throw JSONRPCError(-5,"Invalid private key");
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key");
             CKey key;
             bool fCompressed;
             CSecret secret = vchSecret.GetSecret(fCompressed);
@@ -446,7 +446,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
         }
     }
     else if(pwalletMain->IsCrypted())
-      throw runtime_error("The wallet must be unlocked with walletpassphrase first");
+      throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "The wallet must be unlocked with walletpassphrase first");
 
     // Add previous txouts given in the RPC call:
     if (params.size() > 1 && params[1].type() != null_type)
@@ -455,23 +455,23 @@ Value signrawtransaction(const Array& params, bool fHelp)
         BOOST_FOREACH(Value& p, prevTxs)
         {
             if (p.type() != obj_type)
-                throw JSONRPCError(-22, "expected object with {\"txid'\",\"vout\",\"scriptPubKey\"}");
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "expected object with {\"txid'\",\"vout\",\"scriptPubKey\"}");
 
             Object prevOut = p.get_obj();
 
             string txidHex = find_value(prevOut, "txid").get_str();
             if (!IsHex(txidHex))
-                throw JSONRPCError(-22, "txid must be hexadecimal");
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "txid must be hexadecimal");
             uint256 txid;
             txid.SetHex(txidHex);
 
             int nOut = find_value(prevOut, "vout").get_int();
             if (nOut < 0)
-                throw JSONRPCError(-22, "vout must be positive");
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "vout must be positive");
 
             string pkHex = find_value(prevOut, "scriptPubKey").get_str();
             if (!IsHex(pkHex))
-                throw JSONRPCError(-22, "scriptPubKey must be hexadecimal");
+                throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "scriptPubKey must be hexadecimal");
             vector<unsigned char> pkData(ParseHex(pkHex));
             CScript scriptPubKey(pkData.begin(), pkData.end());
 
@@ -484,7 +484,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
                     string err("Previous output scriptPubKey mismatch:\n");
                     err = err + mapPrevOut[outpoint].ToString() + "\nvs:\n"+
                         scriptPubKey.ToString();
-                    throw JSONRPCError(-22, err);
+                    throw JSONRPCError(RPC_DESERIALIZATION_ERROR, err);
                 }
             }
             else
@@ -523,7 +523,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
         if (mapSigHashValues.count(strHashType))
             nHashType = mapSigHashValues[strHashType];
         else
-            throw JSONRPCError(-8, "Invalid sighash param");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid sighash param");
     }
 
     bool fHashSingle = ((nHashType & ~SIGHASH_ANYONECANPAY) == SIGHASH_SINGLE);
@@ -583,7 +583,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
         ssData >> tx;
     }
     catch (std::exception &e) {
-        throw JSONRPCError(-22, "TX decode failed");
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
     }
     uint256 hashTx = tx.GetHash();
 
@@ -594,7 +594,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
     if (GetTransaction(hashTx, existingTx, hashBlock))
     {
         if (hashBlock != 0)
-            throw JSONRPCError(-5, string("transaction already in block ")+hashBlock.GetHex());
+            throw JSONRPCError(RPC_VERIFY_ALREADY_IN_CHAIN, string("transaction already in block ")+hashBlock.GetHex());
         // Not in block, but already in the memory pool; will drop
         // through to re-relay it.
     }
@@ -603,7 +603,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
         // push to local node
         CTxDB txdb("r");
         if (!tx.AcceptToMemoryPool(txdb, fCheckInputs))
-            throw JSONRPCError(-22, "TX rejected");
+            throw JSONRPCError(RPC_VERIFY_REJECTED, "TX rejected");
 
         SyncWithWallets(tx, NULL, true);
     }
diff --git a/src/rpcwallet.cpp b/src/rpcwallet.cpp
index e5dea576..3e75fffb 100644
--- a/src/rpcwallet.cpp
+++ b/src/rpcwallet.cpp
@@ -30,7 +30,7 @@ static std::string HelpRequiringPassphrase()
 static inline void EnsureWalletIsUnlocked()
 {
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
 }
 
 void WalletTxToJSON(const CWalletTx& wtx, Object& entry)
@@ -52,7 +52,7 @@ string AccountFromValue(const Value& value)
 {
     string strAccount = value.get_str();
     if (strAccount == "*")
-        throw JSONRPCError(-11, "Invalid account name");
+        throw JSONRPCError(RPC_WALLET_INVALID_ACCOUNT_NAME, "Invalid account name");
     return strAccount;
 }
 
@@ -106,7 +106,7 @@ Value getnewaddress(const Array& params, bool fHelp)
     // Generate a new key that is added to wallet
     CPubKey newKey;
     if (!pwalletMain->GetKeyFromPool(newKey, false))
-        throw JSONRPCError(-12, "Error: Keypool ran out, please call keypoolrefill first");
+        throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, "Error: Keypool ran out, please call keypoolrefill first");
     CKeyID keyID = newKey.GetID();
 
     pwalletMain->SetAddressBookName(keyID, strAccount);
@@ -143,7 +143,7 @@ CBitcoinAddress GetAccountAddress(string strAccount, bool bForceNew=false)
     if (!account.vchPubKey.IsValid() || bForceNew || bKeyUsed)
     {
         if (!pwalletMain->GetKeyFromPool(account.vchPubKey, false))
-            throw JSONRPCError(-12, "Error: Keypool ran out, please call keypoolrefill first");
+            throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, "Error: Keypool ran out, please call keypoolrefill first");
 
         pwalletMain->SetAddressBookName(account.vchPubKey.GetID(), strAccount);
         walletdb.WriteAccount(strAccount, account);
@@ -178,7 +178,7 @@ Value setaccount(const Array& params, bool fHelp)
 
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
 
 
     string strAccount;
@@ -207,7 +207,7 @@ Value getaccount(const Array& params, bool fHelp)
 
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
 
     string strAccount;
     map<CTxDestination, string>::iterator mi = pwalletMain->mapAddressBook.find(address.Get());
@@ -247,11 +247,12 @@ Value sendtoaddress(const Array& params, bool fHelp)
 
     CBitcoinAddress address(params[0].get_str());
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
 
     // Amount
     int64 nAmount = AmountFromValue(params[1]);
     if (nAmount < MIN_TXOUT_AMOUNT)
+        // Should this be a different (defined) error number?
         throw JSONRPCError(-101, "Send amount too small");
 
     // Wallet comments
@@ -262,11 +263,11 @@ Value sendtoaddress(const Array& params, bool fHelp)
         wtx.mapValue["to"]      = params[3].get_str();
 
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
 
     string strError = pwalletMain->SendMoneyToDestination(address.Get(), nAmount, wtx);
     if (strError != "")
-        throw JSONRPCError(-4, strError);
+        throw JSONRPCError(RPC_WALLET_ERROR, strError);
 
     return wtx.GetHash().GetHex();
 }
@@ -285,15 +286,15 @@ Value signmessage(const Array& params, bool fHelp)
 
     CBitcoinAddress addr(strAddress);
     if (!addr.IsValid())
-        throw JSONRPCError(-3, "Invalid address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid address");
 
     CKeyID keyID;
     if (!addr.GetKeyID(keyID))
-        throw JSONRPCError(-3, "Address does not refer to key");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Address does not refer to key");
 
     CKey key;
     if (!pwalletMain->GetKey(keyID, key))
-        throw JSONRPCError(-4, "Private key not available");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Private key not available");
 
     CDataStream ss(SER_GETHASH, 0);
     ss << strMessageMagic;
@@ -301,7 +302,7 @@ Value signmessage(const Array& params, bool fHelp)
 
     vector<unsigned char> vchSig;
     if (!key.SignCompact(Hash(ss.begin(), ss.end()), vchSig))
-        throw JSONRPCError(-5, "Sign failed");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Sign failed");
 
     return EncodeBase64(&vchSig[0], vchSig.size());
 }
@@ -319,17 +320,17 @@ Value verifymessage(const Array& params, bool fHelp)
 
     CBitcoinAddress addr(strAddress);
     if (!addr.IsValid())
-        throw JSONRPCError(-3, "Invalid address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid address");
 
     CKeyID keyID;
     if (!addr.GetKeyID(keyID))
-        throw JSONRPCError(-3, "Address does not refer to key");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Address does not refer to key");
 
     bool fInvalid = false;
     vector<unsigned char> vchSig = DecodeBase64(strSign.c_str(), &fInvalid);
 
     if (fInvalid)
-        throw JSONRPCError(-5, "Malformed base64 encoding");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Malformed base64 encoding");
 
     CDataStream ss(SER_GETHASH, 0);
     ss << strMessageMagic;
@@ -353,7 +354,7 @@ Value getreceivedbyaddress(const Array& params, bool fHelp)
     CBitcoinAddress address = CBitcoinAddress(params[0].get_str());
     CScript scriptPubKey;
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
     scriptPubKey.SetDestination(address.Get());
     if (!IsMine(*pwalletMain,scriptPubKey))
         return (double)0.0;
@@ -607,7 +608,7 @@ Value movecmd(const Array& params, bool fHelp)
 
     CWalletDB walletdb(pwalletMain->strWalletFile);
     if (!walletdb.TxnBegin())
-        throw JSONRPCError(-20, "database error");
+        throw JSONRPCError(RPC_DATABASE_ERROR, "database error");
 
     int64 nNow = GetAdjustedTime();
 
@@ -630,7 +631,7 @@ Value movecmd(const Array& params, bool fHelp)
     walletdb.WriteAccountingEntry(credit);
 
     if (!walletdb.TxnCommit())
-        throw JSONRPCError(-20, "database error");
+        throw JSONRPCError(RPC_DATABASE_ERROR, "database error");
 
     return true;
 }
@@ -646,7 +647,7 @@ Value sendfrom(const Array& params, bool fHelp)
     string strAccount = AccountFromValue(params[0]);
     CBitcoinAddress address(params[1].get_str());
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address");
     int64 nAmount = AmountFromValue(params[2]);
     if (nAmount < MIN_TXOUT_AMOUNT)
         throw JSONRPCError(-101, "Send amount too small");
@@ -666,12 +667,12 @@ Value sendfrom(const Array& params, bool fHelp)
     // Check funds
     int64 nBalance = GetAccountBalance(strAccount, nMinDepth);
     if (nAmount > nBalance)
-        throw JSONRPCError(-6, "Account has insufficient funds");
+        throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Account has insufficient funds");
 
     // Send
     string strError = pwalletMain->SendMoneyToDestination(address.Get(), nAmount, wtx);
     if (strError != "")
-        throw JSONRPCError(-4, strError);
+        throw JSONRPCError(RPC_WALLET_ERROR, strError);
 
     return wtx.GetHash().GetHex();
 }
@@ -711,10 +712,10 @@ Value sendmany(const Array& params, bool fHelp)
     {
         CBitcoinAddress address(s.name_);
         if (!address.IsValid())
-            throw JSONRPCError(-5, string("Invalid Paycoin address:")+s.name_);
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid Paycoin address:")+s.name_);
 
         if (setAddress.count(address))
-            throw JSONRPCError(-8, string("Invalid parameter, duplicated address: ")+s.name_);
+            throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid parameter, duplicated address: ")+s.name_);
         setAddress.insert(address);
 
         CScript scriptPubKey;
@@ -730,20 +731,20 @@ Value sendmany(const Array& params, bool fHelp)
     EnsureWalletIsUnlocked();
 
     if (fWalletUnlockMintOnly)
-        throw JSONRPCError(-13, "Error: Wallet unlocked for block minting only.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Wallet unlocked for block minting only.");
 
     // Check funds
     if (fFromAllAccounts)
     {
         int64 nBalance = pwalletMain->GetBalance();
         if (totalAmount > nBalance)
-            throw JSONRPCError(-6, "Wallet has insufficient funds");
+            throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Wallet has insufficient funds");
     }
     else
     {
         int64 nBalance = GetAccountBalance(strAccount, nMinDepth);
         if (totalAmount > nBalance)
-            throw JSONRPCError(-6, "Account has insufficient funds");
+            throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Account has insufficient funds");
     }
 
     // Send
@@ -753,11 +754,11 @@ Value sendmany(const Array& params, bool fHelp)
     if (!fCreated)
     {
         if (totalAmount + nFeeRequired > pwalletMain->GetBalance())
-            throw JSONRPCError(-6, "Insufficient funds");
-        throw JSONRPCError(-4, "Transaction creation failed");
+            throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Insufficient funds");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Transaction creation failed");
     }
     if (!pwalletMain->CommitTransaction(wtx, keyChange))
-        throw JSONRPCError(-4, "Transaction commit failed");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Transaction commit failed");
 
     return wtx.GetHash().GetHex();
 }
@@ -772,9 +773,9 @@ CScript _createmultisig(const Array& params)
 
     // Gather public keys
     if (nRequired < 1)
-        throw runtime_error("a multisignature address must require at least one key to redeem");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "a multisignature address must require at least one key to redeem");
     if ((int)keys.size() < nRequired)
-        throw runtime_error(strprintf("not enough keys supplied (got %u keys, but need at least %d to redeem)", keys.size(), nRequired));
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("not enough keys supplied (got %u keys, but need at least %d to redeem)", keys.size(), nRequired));
     std::vector<CPubKey> pubkeys;
     pubkeys.resize(keys.size());
     for (unsigned int i = 0; i < keys.size(); i++)
@@ -787,12 +788,12 @@ CScript _createmultisig(const Array& params)
         {
             CKeyID keyID;
             if (!address.GetKeyID(keyID))
-                throw runtime_error(strprintf("%s does not refer to a key",ks.c_str()));
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, ks+string(" does not refer to a key"));
             CPubKey vchPubKey;
             if (!pwalletMain->GetPubKey(keyID, vchPubKey))
-                throw runtime_error(strprintf("no full public key for address %s",ks.c_str()));
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("no full public key for address ")+ks);
             if (!vchPubKey.IsFullyValid())
-                throw runtime_error(" Invalid public key: "+ks);
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid public key: ")+ks);
             pubkeys[i] = vchPubKey;
         }
 
@@ -801,12 +802,12 @@ CScript _createmultisig(const Array& params)
         {
             CPubKey vchPubKey(ParseHex(ks));
             if (!vchPubKey.IsFullyValid())
-                throw runtime_error(" Invalid public key: "+ks);
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid public key: ")+ks);
             pubkeys[i] = vchPubKey;
         }
         else
         {
-            throw runtime_error(" Invalid public key: "+ks);
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid public key: ")+ks);
         }
     }
     CScript result;
@@ -1124,9 +1125,9 @@ Value listtransactions(const Array& params, bool fHelp)
         nFrom = params[2].get_int();
 
     if (nCount < 0)
-        throw JSONRPCError(-8, "Negative count");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Negative count");
     if (nFrom < 0)
-        throw JSONRPCError(-8, "Negative from");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Negative from");
 
     Array ret;
     CWalletDB walletdb(pwalletMain->strWalletFile);
@@ -1315,7 +1316,7 @@ Value listsinceblock(const Array& params, bool fHelp)
         target_confirms = params[1].get_int();
 
         if (target_confirms < 1)
-            throw JSONRPCError(-8, "Invalid parameter");
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter");
     }
 
     int depth = pindex ? (1 + nBestHeight - pindex->nHeight) : -1;
@@ -1368,7 +1369,7 @@ Value gettransaction(const Array& params, bool fHelp)
     Object entry;
 
     if (!pwalletMain->mapWallet.count(hash))
-        throw JSONRPCError(-5, "Invalid or non-wallet transaction id");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid or non-wallet transaction id");
     const CWalletTx& wtx = pwalletMain->mapWallet[hash];
 
     int64 nCredit = wtx.GetCredit();
@@ -1415,7 +1416,7 @@ Value keypoolrefill(const Array& params, bool fHelp)
     pwalletMain->TopUpKeyPool();
 
     if (pwalletMain->GetKeyPoolSize() < GetArg("-keypool", 100))
-        throw JSONRPCError(-4, "Error refreshing keypool.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Error refreshing keypool.");
 
     return Value::null;
 }
@@ -1476,10 +1477,10 @@ Value walletpassphrase(const Array& params, bool fHelp)
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
-        throw JSONRPCError(-15, "Error: running with an unencrypted wallet, but walletpassphrase was called.");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an unencrypted wallet, but walletpassphrase was called.");
 
     if (!pwalletMain->IsLocked())
-        throw JSONRPCError(-17, "Error: Wallet is already unlocked, use walletlock first if need to change unlock settings.");
+        throw JSONRPCError(RPC_WALLET_ALREADY_UNLOCKED, "Error: Wallet is already unlocked, use walletlock first if need to change unlock settings.");
 
     // Note that the walletpassphrase is stored in params[0] which is not mlock()ed
     SecureString strWalletPass;
@@ -1491,7 +1492,7 @@ Value walletpassphrase(const Array& params, bool fHelp)
     if (strWalletPass.length() > 0)
     {
         if (!pwalletMain->Unlock(strWalletPass))
-            throw JSONRPCError(-14, "Error: The wallet passphrase entered was incorrect.");
+            throw JSONRPCError(RPC_WALLET_PASSPHRASE_INCORRECT, "Error: The wallet passphrase entered was incorrect.");
     }
     else
         throw runtime_error(
@@ -1520,7 +1521,7 @@ Value walletpassphrasechange(const Array& params, bool fHelp)
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
-        throw JSONRPCError(-15, "Error: running with an unencrypted wallet, but walletpassphrasechange was called.");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an unencrypted wallet, but walletpassphrasechange was called.");
 
     // TODO: get rid of these .c_str() calls by implementing SecureString::operator=(std::string)
     // Alternately, find a way to make params[0] mlock()'d to begin with.
@@ -1538,7 +1539,7 @@ Value walletpassphrasechange(const Array& params, bool fHelp)
             "Changes the wallet passphrase from <oldpassphrase> to <newpassphrase>.");
 
     if (!pwalletMain->ChangeWalletPassphrase(strOldWalletPass, strNewWalletPass))
-        throw JSONRPCError(-14, "Error: The wallet passphrase entered was incorrect.");
+        throw JSONRPCError(RPC_WALLET_PASSPHRASE_INCORRECT, "Error: The wallet passphrase entered was incorrect.");
 
     return Value::null;
 }
@@ -1554,7 +1555,7 @@ Value walletlock(const Array& params, bool fHelp)
     if (fHelp)
         return true;
     if (!pwalletMain->IsCrypted())
-        throw JSONRPCError(-15, "Error: running with an unencrypted wallet, but walletlock was called.");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an unencrypted wallet, but walletlock was called.");
 
     {
         LOCK(cs_nWalletUnlockTime);
@@ -1574,7 +1575,7 @@ Value encryptwallet(const Array& params, bool fHelp)
     if (fHelp)
         return true;
     if (pwalletMain->IsCrypted())
-        throw JSONRPCError(-15, "Error: running with an encrypted wallet, but encryptwallet was called.");
+        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an encrypted wallet, but encryptwallet was called.");
 
     // TODO: get rid of this .c_str() by implementing SecureString::operator=(std::string)
     // Alternately, find a way to make params[0] mlock()'d to begin with.
@@ -1588,7 +1589,7 @@ Value encryptwallet(const Array& params, bool fHelp)
             "Encrypts the wallet with <passphrase>.");
 
     if (!pwalletMain->EncryptWallet(strWalletPass))
-        throw JSONRPCError(-16, "Error: Failed to encrypt the wallet.");
+        throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Failed to encrypt the wallet.");
 
     // BDB seems to have a bad habit of writing old data into
     // slack space in .dat files; that is bad if the old data is
@@ -1678,17 +1679,17 @@ Value reservebalance(const Array& params, bool fHelp)
         if (fReserve)
         {
             if (params.size() == 1)
-                throw runtime_error("must provide amount to reserve balance.\n");
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "must provide amount to reserve balance.\n");
             int64 nAmount = AmountFromValue(params[1]);
             nAmount = (nAmount / CENT) * CENT;  // round to cent
             if (nAmount < 0)
-                throw runtime_error("amount cannot be negative.\n");
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "amount cannot be negative.\n");
             mapArgs["-reservebalance"] = FormatMoney(nAmount).c_str();
         }
         else
         {
             if (params.size() > 1)
-                throw runtime_error("cannot specify amount to turn off reserve.\n");
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "cannot specify amount to turn off reserve.\n");
             mapArgs["-reservebalance"] = "0";
         }
     }
@@ -1696,7 +1697,7 @@ Value reservebalance(const Array& params, bool fHelp)
     Object result;
     int64 nReserveBalance = 0;
     if (mapArgs.count("-reservebalance") && !ParseMoney(mapArgs["-reservebalance"], nReserveBalance))
-        throw runtime_error("invalid reserve balance amount\n");
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "invalid reserve balance amount\n");
     result.push_back(Pair("reserve", (nReserveBalance > 0)));
     result.push_back(Pair("amount", ValueFromAmount(nReserveBalance)));
     return result;
@@ -1803,17 +1804,17 @@ Value listmicroprimedata(const Array& params, bool fHelp)
     CBitcoinAddress address(strAddress);
 
     if (!IsMine(*pwalletMain, address.Get()))
-        throw runtime_error("Address must be in wallet.");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Address must be in wallet.");
 
     if (!primeNodeDB->CheckMicroPrime(strAddress))
-        throw runtime_error("Address is not a valid microprime address.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Address is not a valid microprime address.");
 
     int primeNodeRate;
     int64 group;
     CScript scriptMPAddress;
     scriptMPAddress.SetDestination(address.Get());
     if (!primeNodeDB->IsMicroPrime(scriptMPAddress, primeNodeRate, group, GetTime()))
-        throw runtime_error("Address is not a valid microprime address.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Address is not a valid microprime address.");
 
     Object obj;
     obj.push_back(Pair("Address", strAddress));
diff --git a/src/scrapesdb.cpp b/src/scrapesdb.cpp
index 828fe77c..55cb973f 100644
--- a/src/scrapesdb.cpp
+++ b/src/scrapesdb.cpp
@@ -21,7 +21,7 @@ Value setscrapeaddress(const Array& params, bool fHelp)
     }
 
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
 
     string strAddress = params[0].get_str();
     CBitcoinAddress address(strAddress);
@@ -29,16 +29,16 @@ Value setscrapeaddress(const Array& params, bool fHelp)
     CBitcoinAddress scrapeAddress(strScrapeAddress);
 
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address.");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address.");
 
     if (address.Get() == scrapeAddress.Get())
-        throw JSONRPCError(-1, "Cannot set scrape address to the same as staking address.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Cannot set scrape address to the same as staking address.");
 
     if (!IsMine(*pwalletMain, address.Get()))
-        throw JSONRPCError(-1, "Staking address must be in wallet.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Staking address must be in wallet.");
 
     if (!scrapeAddress.IsValid())
-        throw JSONRPCError(-5, "Invalid scrape address.");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid scrape address.");
 
     string oldScrapeAddress;
     bool warn = false;
@@ -59,7 +59,7 @@ Value setscrapeaddress(const Array& params, bool fHelp)
     }
 
     // This should never happen.
-    throw JSONRPCError(-1, "setscrapeaddress: unknown error");
+    throw JSONRPCError(RPC_MISC_ERROR, "setscrapeaddress: unknown error");
 }
 
 Value getscrapeaddress(const Array& params, bool fHelp)
@@ -74,16 +74,16 @@ Value getscrapeaddress(const Array& params, bool fHelp)
     CBitcoinAddress address(strAddress);
 
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address.");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address.");
 
     if (!IsMine(*pwalletMain, address.Get()))
-        throw JSONRPCError(-1, "Staking address must be in wallet.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Staking address must be in wallet.");
 
     string strScrapeAddress;
     if (!scrapesDB->ReadScrapeAddress(strAddress, strScrapeAddress)) {
         string ret = "No scrape address set for address ";
         ret += strAddress;
-        throw JSONRPCError(-1, ret);
+        throw JSONRPCError(RPC_WALLET_ERROR, ret);
     }
 
     Object obj;
@@ -116,21 +116,21 @@ Value deletescrapeaddress(const Array& params, bool fHelp)
     }
 
     if (pwalletMain->IsLocked())
-        throw JSONRPCError(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.");
+        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
 
     string strAddress = params[0].get_str();
     CBitcoinAddress address(strAddress);
 
     if (!address.IsValid())
-        throw JSONRPCError(-5, "Invalid Paycoin address.");
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Paycoin address.");
 
     if (!IsMine(*pwalletMain, address.Get()))
-        throw JSONRPCError(-1, "Staking address must be in wallet.");
+        throw JSONRPCError(RPC_WALLET_ERROR, "Staking address must be in wallet.");
 
     if (!scrapesDB->HasScrapeAddress(strAddress)) {
         string ret = "No scrape address set for address ";
         ret += strAddress;
-        throw JSONRPCError(-1, ret);
+        throw JSONRPCError(RPC_WALLET_ERROR, ret);
     }
 
     return scrapesDB->EraseScrapeAddress(strAddress);
diff --git a/src/test/rpc_tests.cpp b/src/test/rpc_tests.cpp
index 0f9159e0..5c9ba3ca 100644
--- a/src/test/rpc_tests.cpp
+++ b/src/test/rpc_tests.cpp
@@ -46,18 +46,18 @@ BOOST_AUTO_TEST_CASE(rpc_addmultisig)
     address.SetString(v.get_str());
     BOOST_CHECK(address.IsValid() && address.IsScript());
 
-    BOOST_CHECK_THROW(addmultisig(createArgs(0), false), runtime_error);
-    BOOST_CHECK_THROW(addmultisig(createArgs(1), false), runtime_error);
-    BOOST_CHECK_THROW(addmultisig(createArgs(2, address1Hex), false), runtime_error);
+    BOOST_CHECK_THROW(addmultisig(createArgs(0), false), Object);
+    BOOST_CHECK_THROW(addmultisig(createArgs(1), false), Object);
+    BOOST_CHECK_THROW(addmultisig(createArgs(2, address1Hex), false), Object);
 
-    BOOST_CHECK_THROW(addmultisig(createArgs(1, ""), false), runtime_error);
-    BOOST_CHECK_THROW(addmultisig(createArgs(1, "NotAValidPubkey"), false), runtime_error);
+    BOOST_CHECK_THROW(addmultisig(createArgs(1, ""), false), Object);
+    BOOST_CHECK_THROW(addmultisig(createArgs(1, "NotAValidPubkey"), false), Object);
 
     string short1(address1Hex, address1Hex+sizeof(address1Hex)-2); // last byte missing
-    BOOST_CHECK_THROW(addmultisig(createArgs(2, short1.c_str()), false), runtime_error);
+    BOOST_CHECK_THROW(addmultisig(createArgs(2, short1.c_str()), false), Object);
 
     string short2(address1Hex+2, address1Hex+sizeof(address1Hex)); // first byte missing
-    BOOST_CHECK_THROW(addmultisig(createArgs(2, short2.c_str()), false), runtime_error);
+    BOOST_CHECK_THROW(addmultisig(createArgs(2, short2.c_str()), false), Object);
 }
 
 // Run RPC tests over RPC...
@@ -104,7 +104,7 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     string strValidPrivKey = "U9nhhCCbFfY64wozUZ6ScrNNvBqhGtoi8cNHXmaLm3wi1VHtjhr8";
     string strValidAddress2 = "PAjArWaTwv8P32b13iTn1bL7aN25Y9pMmJ";
 
-    // error: {"code":-1,"message":"Staking address must be in wallet."}
+    // error: {"code":-4,"message":"Staking address must be in wallet."}
     string strMethod = "setscrapeaddress";
     vector<string> strParams;
     strParams.push_back(strValidAddress);
@@ -114,7 +114,7 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
 
     int error_code;
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
     strMethod = "getscrapeaddress";
     strParams.clear();
@@ -123,14 +123,14 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
     strMethod = "deletescrapeaddress";
 
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
     // Import a valid private key for testing on.
     strMethod = "importprivkey";
@@ -151,7 +151,7 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -5);
+    BOOST_CHECK_EQUAL(error_code, RPC_INVALID_ADDRESS_OR_KEY);
 
     strMethod = "getscrapeaddress";
     strParams.clear();
@@ -160,14 +160,14 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -5);
+    BOOST_CHECK_EQUAL(error_code, RPC_INVALID_ADDRESS_OR_KEY);
 
     strMethod = "deletescrapeaddress";
 
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -5);
+    BOOST_CHECK_EQUAL(error_code, RPC_INVALID_ADDRESS_OR_KEY);
 
     // error: {"code":-5,"message":"Invalid scrape address."}
     strMethod = "setscrapeaddress";
@@ -178,9 +178,9 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -5);
+    BOOST_CHECK_EQUAL(error_code, RPC_INVALID_ADDRESS_OR_KEY);
 
-    // error: {"code":-1,"message":"Cannot set scrape address to the same as staking address."}
+    // error: {"code":-4,"message":"Cannot set scrape address to the same as staking address."}
     strParams.clear();
     strParams.push_back(strValidAddress);
     strParams.push_back(strValidAddress);
@@ -188,9 +188,9 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
-    // error: ("code":-1,"message":"No scrape address set for address <staking address>")
+    // error: ("code":-4,"message":"No scrape address set for address <staking address>")
     strMethod = "getscrapeaddress";
     strParams.clear();
     strParams.push_back(strValidAddress);
@@ -198,14 +198,14 @@ BOOST_FIXTURE_TEST_CASE(rpc_scrapes, RPCServerFixture)
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
     strMethod = "deletescrapeaddress";
 
     obj = callRPC(strMethod, strParams);
 
     BOOST_CHECK(!readResponse(obj, error_code));
-    BOOST_CHECK_EQUAL(error_code, -1);
+    BOOST_CHECK_EQUAL(error_code, RPC_WALLET_ERROR);
 
     // Valid setscrapeaddress
     strMethod = "setscrapeaddress";