diff --git a/nightscout.js b/nightscout.js
index b95833f..290e1cc 100644
--- a/nightscout.js
+++ b/nightscout.js
@@ -6,111 +6,6 @@ var crypto = require('crypto'),
 
 var logger = require('./logger');
 
-var STALE_DATA_THRESHOLD_MINUTES = 20;
-var PUMP_STATUS_ENTRY_TYPE = 'pump_status';
-var SENSOR_GLUCOSE_ENTRY_TYPE = 'sgv';
-
-function parsePumpTime(pumpTimeString, offset) {
-  return Date.parse(pumpTimeString + ' ' + offset);
-}
-
-function addTimeToEntry(timestamp, entry) {
-  entry['date'] = timestamp;
-  entry['dateString'] = new Date(timestamp).toISOString();
-  return entry;
-}
-
-var guessPumpOffset = (function() {
-  var lastGuess;
-
-  // From my observations, sMedicalDeviceTime is advanced by the server even when the app is
-  // not reporting data or the pump is not connected, so its difference from server time is
-  // always close to a whole number of hours, and can be used to guess the pump's timezone:
-  // https://gist.github.com/mddub/f673570e6427c93784bf
-  return function(data) {
-    var pumpTimeAsIfUTC = Date.parse(data['sMedicalDeviceTime'] + ' +0');
-    var serverTimeUTC = data['currentServerTime'];
-    var hours = Math.round((pumpTimeAsIfUTC - serverTimeUTC) / (60*60*1000));
-    var offset = (hours >= 0 ? '+' : '-') + (Math.abs(hours) < 10 ? '0' : '') + Math.abs(hours) + '00';
-    if (offset !== lastGuess) {
-      logger.log('Guessed pump timezone ' + offset + ' (pump time: "' + data['sMedicalDeviceTime'] + '"; server time: ' + new Date(data['currentServerTime']) + ')');
-    }
-    lastGuess = offset;
-    return offset;
-  };
-})();
-
-function pumpStatusEntry(data) {
-  var entry = {'type': PUMP_STATUS_ENTRY_TYPE};
-
-  [
-    'conduitBatteryLevel',
-    'conduitInRange',
-    'conduitMedicalDeviceInRange',
-    'reservoirLevelPercent',
-    'reservoirAmount',
-    'medicalDeviceBatteryLevelPercent'
-  ].forEach(function(key) {
-    if(data[key] !== undefined) {
-      entry[key] = data[key];
-    }
-  });
-
-  if(data['activeInsulin'] && data['activeInsulin']['amount'] >= 0) {
-    entry['activeInsulin'] = data['activeInsulin']['amount'];
-  }
-
-  return addTimeToEntry(data['lastMedicalDeviceDataUpdateServerTime'], entry);
-}
-
-function sgvEntries(data) {
-  var offset = guessPumpOffset(data);
-
-  if(data['sgs'] && data['sgs'].length) {
-    return data['sgs'].filter(function(entry) {
-      return entry['kind'] === 'SG' && entry['sg'] !== 0;
-    }).map(function(sgv) {
-      return addTimeToEntry(
-        parsePumpTime(sgv['datetime'], offset),
-        {
-          'type': SENSOR_GLUCOSE_ENTRY_TYPE,
-          'sgv': sgv['sg'],
-        }
-      );
-    });
-  } else {
-    return [];
-  }
-}
-
-var transform = module.exports.transform = function(data, sgvLimit) {
-  var recency = (data['currentServerTime'] - data['lastMedicalDeviceDataUpdateServerTime']) / (60 * 1000);
-  if (recency > STALE_DATA_THRESHOLD_MINUTES) {
-    logger.log('Stale CareLink data: ' + recency.toFixed(2) + ' minutes old');
-    return [];
-  }
-
-  if (sgvLimit === undefined) {
-    sgvLimit = Infinity;
-  }
-
-  var entries = [];
-
-  entries.push(pumpStatusEntry(data));
-
-  var sgvs = sgvEntries(data);
-  // TODO: this assumes sgvs are ordered by date ascending
-  for(var i = Math.max(0, sgvs.length - sgvLimit); i < sgvs.length; i++) {
-    entries.push(sgvs[i]);
-  }
-
-  entries.forEach(function(entry) {
-    entry['device'] = 'MiniMed Connect ' + data['medicalDeviceFamily'] + ' ' + data['medicalDeviceSerialNumber'];
-  });
-
-  return entries;
-};
-
 var upload = module.exports.upload = function(entries, endpoint, secret, callback) {
   logger.log('POST ' + endpoint + ' ' + JSON.stringify(entries));
   request.post(
diff --git a/run.js b/run.js
index 4ad3b16..c88c10a 100644
--- a/run.js
+++ b/run.js
@@ -2,7 +2,8 @@
 "use strict";
 
 var carelink = require('./carelink'),
-  nightscout = require('./nightscout');
+  nightscout = require('./nightscout'),
+  transform = require('./transform');
 
 function readEnv(key, defaultVal) {
   var val = process.env[key] ||
@@ -37,7 +38,7 @@ var endpoint = (config.nsBaseUrl ? config.nsBaseUrl : 'https://' + config.nsHost
     if (err) {
       throw new Error(err);
     } else {
-      var entries = nightscout.transform(data, config.sgvLimit);
+      var entries = transform(data, config.sgvLimit);
       if (entries.length > 0) {
         nightscout.upload(entries, endpoint, config.nsSecret, function(err, response) {
           if (err) {
diff --git a/transform.js b/transform.js
new file mode 100644
index 0000000..489ba22
--- /dev/null
+++ b/transform.js
@@ -0,0 +1,109 @@
+/* jshint node: true */
+"use strict";
+
+var logger = require('./logger');
+
+var STALE_DATA_THRESHOLD_MINUTES = 20;
+var PUMP_STATUS_ENTRY_TYPE = 'pump_status';
+var SENSOR_GLUCOSE_ENTRY_TYPE = 'sgv';
+
+function parsePumpTime(pumpTimeString, offset) {
+  return Date.parse(pumpTimeString + ' ' + offset);
+}
+
+function addTimeToEntry(timestamp, entry) {
+  entry['date'] = timestamp;
+  entry['dateString'] = new Date(timestamp).toISOString();
+  return entry;
+}
+
+var guessPumpOffset = (function() {
+  var lastGuess;
+
+  // From my observations, sMedicalDeviceTime is advanced by the server even when the app is
+  // not reporting data or the pump is not connected, so its difference from server time is
+  // always close to a whole number of hours, and can be used to guess the pump's timezone:
+  // https://gist.github.com/mddub/f673570e6427c93784bf
+  return function(data) {
+    var pumpTimeAsIfUTC = Date.parse(data['sMedicalDeviceTime'] + ' +0');
+    var serverTimeUTC = data['currentServerTime'];
+    var hours = Math.round((pumpTimeAsIfUTC - serverTimeUTC) / (60*60*1000));
+    var offset = (hours >= 0 ? '+' : '-') + (Math.abs(hours) < 10 ? '0' : '') + Math.abs(hours) + '00';
+    if (offset !== lastGuess) {
+      logger.log('Guessed pump timezone ' + offset + ' (pump time: "' + data['sMedicalDeviceTime'] + '"; server time: ' + new Date(data['currentServerTime']) + ')');
+    }
+    lastGuess = offset;
+    return offset;
+  };
+})();
+
+function pumpStatusEntry(data) {
+  var entry = {'type': PUMP_STATUS_ENTRY_TYPE};
+
+  [
+    'conduitBatteryLevel',
+    'conduitInRange',
+    'conduitMedicalDeviceInRange',
+    'reservoirLevelPercent',
+    'reservoirAmount',
+    'medicalDeviceBatteryLevelPercent'
+  ].forEach(function(key) {
+    if(data[key] !== undefined) {
+      entry[key] = data[key];
+    }
+  });
+
+  if(data['activeInsulin'] && data['activeInsulin']['amount'] >= 0) {
+    entry['activeInsulin'] = data['activeInsulin']['amount'];
+  }
+
+  return addTimeToEntry(data['lastMedicalDeviceDataUpdateServerTime'], entry);
+}
+
+function sgvEntries(data) {
+  var offset = guessPumpOffset(data);
+
+  if(data['sgs'] && data['sgs'].length) {
+    return data['sgs'].filter(function(entry) {
+      return entry['kind'] === 'SG' && entry['sg'] !== 0;
+    }).map(function(sgv) {
+      return addTimeToEntry(
+        parsePumpTime(sgv['datetime'], offset),
+        {
+          'type': SENSOR_GLUCOSE_ENTRY_TYPE,
+          'sgv': sgv['sg'],
+        }
+      );
+    });
+  } else {
+    return [];
+  }
+}
+
+var transform = module.exports = function(data, sgvLimit) {
+  var recency = (data['currentServerTime'] - data['lastMedicalDeviceDataUpdateServerTime']) / (60 * 1000);
+  if (recency > STALE_DATA_THRESHOLD_MINUTES) {
+    logger.log('Stale CareLink data: ' + recency.toFixed(2) + ' minutes old');
+    return [];
+  }
+
+  if (sgvLimit === undefined) {
+    sgvLimit = Infinity;
+  }
+
+  var entries = [];
+
+  entries.push(pumpStatusEntry(data));
+
+  var sgvs = sgvEntries(data);
+  // TODO: this assumes sgvs are ordered by date ascending
+  for(var i = Math.max(0, sgvs.length - sgvLimit); i < sgvs.length; i++) {
+    entries.push(sgvs[i]);
+  }
+
+  entries.forEach(function(entry) {
+    entry['device'] = 'MiniMed Connect ' + data['medicalDeviceFamily'] + ' ' + data['medicalDeviceSerialNumber'];
+  });
+
+  return entries;
+};