diff --git a/src/code/codeManager.js b/src/code/codeManager.js
index 88371ed4a4..ee9141f4ca 100644
--- a/src/code/codeManager.js
+++ b/src/code/codeManager.js
@@ -25,39 +25,45 @@ CodeManager.prototype.resolveStep = function (stepIndex, tx) {
   this.trigger('resolvingStep')
   var self = this
   if (stepIndex === 0) {
-    self.getCode(tx.to, stepIndex, tx)
+    self.retrieveCodeAndTrigger(tx.to, stepIndex, tx)
   } else {
     this.traceManager.getCurrentCalledAddressAt(stepIndex, function (error, address) {
       if (error) {
         console.log(error)
       } else {
-        self.getCode(address, stepIndex, tx)
+        self.retrieveCodeAndTrigger(address, stepIndex, tx)
       }
     })
   }
 }
 
-CodeManager.prototype.getCode = function (address, currentStep, tx) {
+CodeManager.prototype.retrieveCodeAndTrigger = function (address, stepIndex, tx) {
   var self = this
+  this.getCode(address, function (error, result) {
+    if (!error) {
+      self.retrieveIndexAndTrigger(address, stepIndex, result.instructions)
+    } else {
+      console.log(error)
+    }
+  })
+}
+
+CodeManager.prototype.getCode = function (address, cb) {
   if (traceHelper.isContractCreation(address)) {
     var codes = codeResolver.getExecutingCodeFromCache(address)
     if (!codes) {
       this.traceManager.getContractCreationCode(address, function (error, hexCode) {
-        // contract creation
-        if (error) {
-          console.log(error)
-        } else {
+        if (!error) {
           codes = codeResolver.cacheExecutingCode(address, hexCode)
-          self.retrieveIndexAndTrigger(address, currentStep, codes.code)
+          cb(null, codes)
         }
       })
     } else {
-      self.retrieveIndexAndTrigger(address, currentStep, codes.code)
+      cb(null, codes)
     }
   } else {
     codeResolver.resolveCode(address, function (address, code) {
-      // resoling code from stack
-      self.retrieveIndexAndTrigger(address, currentStep, code)
+      cb(null, code)
     })
   }
 }
diff --git a/src/code/codeResolver.js b/src/code/codeResolver.js
index 3f80ba5093..7b24007340 100644
--- a/src/code/codeResolver.js
+++ b/src/code/codeResolver.js
@@ -3,19 +3,20 @@ var codeUtils = require('./codeUtils')
 var util = require('../helpers/global')
 
 module.exports = {
-  codes: {}, // assembly items instructions list by contract addesses
+  bytecodeByAddress: {}, // bytes code by contract addesses
+  instructionsByAddress: {}, // assembly items instructions list by contract addesses
   instructionsIndexByBytesOffset: {}, // mapping between bytes offset and instructions index.
 
   resolveCode: function (address, callBack) {
     var cache = this.getExecutingCodeFromCache(address)
     if (cache) {
-      callBack(address, cache.code)
+      callBack(address, cache)
       return
     }
 
     var self = this
     this.loadCode(address, function (code) {
-      callBack(address, self.cacheExecutingCode(address, code).code)
+      callBack(address, self.cacheExecutingCode(address, code))
     })
   },
 
@@ -32,9 +33,10 @@ module.exports = {
 
   cacheExecutingCode: function (address, hexCode) {
     var codes = this.formatCode(hexCode)
-    this.codes[address] = codes.code
+    this.bytecodeByAddress[address] = hexCode
+    this.instructionsByAddress[address] = codes.code
     this.instructionsIndexByBytesOffset[address] = codes.instructionsIndexByBytesOffset
-    return codes
+    return this.getExecutingCodeFromCache(address)
   },
 
   formatCode: function (hexCode) {
@@ -46,10 +48,11 @@ module.exports = {
   },
 
   getExecutingCodeFromCache: function (address) {
-    if (this.codes[address]) {
+    if (this.instructionsByAddress[address]) {
       return {
-        code: this.codes[address],
-        instructionsIndexByBytesOffset: this.instructionsIndexByBytesOffset[address]
+        instructions: this.instructionsByAddress[address],
+        instructionsIndexByBytesOffset: this.instructionsIndexByBytesOffset[address],
+        bytecode: this.bytecodeByAddress[address]
       }
     } else {
       return null
diff --git a/src/code/sourceLocationTracker.js b/src/code/sourceLocationTracker.js
new file mode 100644
index 0000000000..259c48a8da
--- /dev/null
+++ b/src/code/sourceLocationTracker.js
@@ -0,0 +1,58 @@
+'use strict'
+var EventManager = require('../lib/eventManager')
+var util = require('../helpers/global')
+var helper = require('../helpers/traceHelper')
+var SourceMappingDecoder = require('../util/sourceMappingDecoder')
+
+/**
+ * Process the source code location for the current executing bytecode
+ */
+function SourceLocationTracker (_codeManager) {
+  this.codeManager = _codeManager
+  util.extend(this, new EventManager())
+  this.sourceMappingDecoder = new SourceMappingDecoder()
+}
+
+/**
+ * Return the source location associated with the given @arg index
+ *
+ * @param {String} address - contract address from which the source location is retrieved
+ * @param {Int} index - index in the instruction list from where the source location is retrieved
+ * @param {Object} contractDetails - AST of compiled contracts
+ * @param {Function} cb - callback function
+ */
+SourceLocationTracker.prototype.getSourceLocation = function (address, index, contractsDetails, cb) {
+  var self = this
+  this.codeManager.getCode(address, function (error, result) {
+    if (!error) {
+      var sourceMap = getSourceMap(address, result.bytecode, contractsDetails)
+      if (sourceMap) {
+        cb(null, self.sourceMappingDecoder.atIndex(index, sourceMap))
+      } else {
+        cb('no srcmap associated with the code ' + address)
+      }
+    } else {
+      cb(error)
+    }
+  })
+}
+
+/**
+ * backwards compatibility - attribute name will certainly be changed
+ */
+function srcmapRuntime (contract) {
+  return contract.srcmapRuntime ? contract.srcmapRuntime : contract['srcmap-runtime']
+}
+
+function getSourceMap (address, code, contractsDetails) {
+  var isCreation = helper.isContractCreation(address)
+  var byteProp = isCreation ? 'bytecode' : 'runtimeBytecode'
+  for (var k in contractsDetails) {
+    if ('0x' + contractsDetails[k][byteProp] === code) {
+      return isCreation ? contractsDetails[k].srcmap : srcmapRuntime(contractsDetails[k])
+    }
+  }
+  return null
+}
+
+module.exports = SourceLocationTracker
diff --git a/src/ui/Ethdebugger.js b/src/ui/Ethdebugger.js
index 0599ba039a..84e4f70e3f 100644
--- a/src/ui/Ethdebugger.js
+++ b/src/ui/Ethdebugger.js
@@ -12,6 +12,7 @@ var ui = require('../helpers/ui')
 var Web3Providers = require('../web3Provider/web3Providers')
 var DummyProvider = require('../web3Provider/dummyProvider')
 var CodeManager = require('../code/codeManager')
+var SourceLocationTracker = require('../code/sourceLocationTracker')
 
 function Ethdebugger () {
   util.extend(this, new EventManager())
@@ -26,6 +27,7 @@ function Ethdebugger () {
   this.switchProvider('DUMMYWEB3')
   this.traceManager = new TraceManager()
   this.codeManager = new CodeManager(this.traceManager)
+  this.sourceLocationTracker = new SourceLocationTracker(this.codeManager)
 
   var self = this
   this.register('indexChanged', this, function (index) {
@@ -72,7 +74,11 @@ Ethdebugger.prototype.switchProvider = function (type) {
 }
 
 Ethdebugger.prototype.debug = function (tx) {
-  this.txBrowser.load(tx.hash)
+  if (tx instanceof Object) {
+    this.txBrowser.load(tx.hash)
+  } else if (tx instanceof String) {
+    this.txBrowser.load(tx)
+  }
 }
 
 Ethdebugger.prototype.render = function () {
diff --git a/src/web3Provider/web3Providers.js b/src/web3Provider/web3Providers.js
index 4fbe0b673c..8ce7f7285a 100644
--- a/src/web3Provider/web3Providers.js
+++ b/src/web3Provider/web3Providers.js
@@ -9,19 +9,16 @@ Web3Providers.prototype.addProvider = function (type, obj) {
   if (type === 'INTERNAL') {
     var web3 = init.loadWeb3()
     this.addWeb3(type, web3)
-  } else if (type === 'EXTERNAL') {
-    init.extendWeb3(obj)
-    this.addWeb3(type, obj)
-  } else if (type === 'VM') {
+  } else if (type === 'vm') {
     this.addVM(obj)
   } else {
+    init.extendWeb3(obj)
     this.addWeb3(type, obj)
   }
 }
 
 Web3Providers.prototype.get = function (type, cb) {
   if (this.modes[type]) {
-    this.currentMode = type
     cb(null, this.modes[type])
   } else {
     cb('error: this provider has not been setup (' + type + ')', null)