diff --git a/lib/plugins.js b/lib/plugins.js
index aeafddea..3aa0950e 100644
--- a/lib/plugins.js
+++ b/lib/plugins.js
@@ -203,7 +203,7 @@ function _sendBitcoins(tx, callback) {
   );
 }
 
-function executeTransaction(deviceFingerprint, txId, autoTriggered, cb) {
+function executeTx(deviceFingerprint, txId, autoTriggered, cb) {
   cb = typeof cb === 'function' ? cb : function() {};
 
   clearSession(deviceFingerprint);
@@ -220,7 +220,7 @@ function executeTransaction(deviceFingerprint, txId, autoTriggered, cb) {
       return cb(null, {statusCode: 304}); // Not Modified
     }
 
-    db.summonTransaction(deviceFingerprint, tx, function(err, txInfo) {
+    db.summonTx(deviceFingerprint, tx, function(err, txInfo) {
       if (err) return cb(err);
 
       // actual sending
@@ -255,7 +255,7 @@ exports.trade = function trade(rawTrade, deviceFingerprint, cb) {
     sessions[deviceFingerprint] = {
       timestamp: Date.now(),
       reaper: setTimeout(function() {
-        executeTransaction(deviceFingerprint, rawTrade.txId, true);
+        executeTx(deviceFingerprint, rawTrade.txId, true);
       }, SESSION_TIMEOUT)
     };
   }
@@ -273,7 +273,7 @@ exports.trade = function trade(rawTrade, deviceFingerprint, cb) {
 };
 
 exports.sendBitcoins = function sendBitcoins(deviceFingerprint, rawTx, callback) {
-  executeTransaction(deviceFingerprint, rawTx.txId, false, callback);
+  executeTx(deviceFingerprint, rawTx.txId, false, callback);
 };
 
 
@@ -474,6 +474,6 @@ exports.verifyUser = function verifyUser(data, callback) {
   idVerifierPlugin.verifyUser(data, callback);
 };
 
-exports.verifyTransaction = function verifyTransaction(data, callback) {
+exports.verifyTx = function verifyTx(data, callback) {
   idVerifierPlugin.verifyTransaction(data, callback);
 };
diff --git a/lib/postgresql_interface.js b/lib/postgresql_interface.js
index f1ce0bab..20ba5b5c 100644
--- a/lib/postgresql_interface.js
+++ b/lib/postgresql_interface.js
@@ -90,7 +90,7 @@ exports.recordDeviceEvent = function recordDeviceEvent(deviceFingerprint, event,
     cb);
 };
 
-function _getTransactions(txId, onlyPending, cb) {
+function _getTxs(txId, onlyPending, cb) {
   var query = 'SELECT * FROM transactions WHERE id=$1';
   var values = [txId];
 
@@ -110,8 +110,8 @@ function _getTransactions(txId, onlyPending, cb) {
 }
 
 // returns complete [txs]
-exports.getTransactions = function getTransactions(txId, cb) {
-  _getTransactions(txId, false, cb);
+exports.getTxs = function getTxs(txId, cb) {
+  _getTxs(txId, false, cb);
 };
 
 exports.getPendingAmount = function getPendingAmount(txId, cb) {
@@ -162,14 +162,16 @@ exports.getPendingAmount = function getPendingAmount(txId, cb) {
     }
 
     // Nothing to send == nothing to do
-    if (newTx.satoshis <= 0)
+    if (newTx.satoshis <= 0) {
+      logger.error('Negative tx amount (%d) for txId: %s', newTx.satoshis, txId);
       return cb();
+    }
 
     cb(null, newTx);
   });
 };
 
-exports.summonTransaction = function summonTransaction(deviceFingerprint, tx, cb) {
+exports.summonTx = function summonTx(deviceFingerprint, tx, cb) {
   var fields = [
     'id',
     'status',
@@ -202,7 +204,7 @@ exports.summonTransaction = function summonTransaction(deviceFingerprint, tx, cb
     function(err) {
       if (err) {
         if (PG_ERRORS[err.code] === 'uniqueViolation')
-          return _getTransactions(tx.txId, false, cb);
+          return _getTxs(tx.txId, false, cb);
 
         return cb(err);
       }
diff --git a/lib/routes.js b/lib/routes.js
index 4d4633af..c3072b21 100644
--- a/lib/routes.js
+++ b/lib/routes.js
@@ -87,10 +87,10 @@ function verifyUser(req, res) {
   });
 }
 
-function verifyTransaction(req, res) {
+function verifyTx(req, res) {
   if (mock) return res.json({success: true});
 
-  plugins.verifyTransaction(req.body, function (err, idResult) {
+  plugins.verifyTx(req.body, function (err, idResult) {
     if (err) {
       logger.error(err);
       return res.json({err: 'Verification failed'});
@@ -140,7 +140,7 @@ function init(localConfig) {
   app.post('/trade', authMiddleware, trade);
   app.post('/event', authMiddleware, deviceEvent);
   app.post('/verify_user', authMiddleware, verifyUser);
-  app.post('/verify_transaction', authMiddleware, verifyTransaction);
+  app.post('/verify_transaction', authMiddleware, verifyTx);
   app.post('/pair', pair);
 
   return app;