diff --git a/packages/optimizely-sdk/lib/core/project_config/index.js b/packages/optimizely-sdk/lib/core/project_config/index.js
index 7624a266b..bcc9e20dd 100644
--- a/packages/optimizely-sdk/lib/core/project_config/index.js
+++ b/packages/optimizely-sdk/lib/core/project_config/index.js
@@ -28,13 +28,41 @@ var EXPERIMENT_RUNNING_STATUS = 'Running';
 var RESERVED_ATTRIBUTE_PREFIX = '$opt_';
 var MODULE_NAME = 'PROJECT_CONFIG';
 
+function createMutationSafeDatafileCopy(datafile) {
+  var datafileCopy = fns.assign({}, datafile);
+  datafileCopy.audiences = (datafile.audiences || []).map(function(audience) {
+    return fns.assign({}, audience);
+  });
+  datafileCopy.experiments = (datafile.experiments || []).map(function(experiment) {
+    return fns.assign({}, experiment);
+  });
+  datafileCopy.featureFlags = (datafile.featureFlags || []).map(function(featureFlag) {
+    return fns.assign({}, featureFlag);
+  });
+  datafileCopy.groups = (datafile.groups || []).map(function(group) {
+    var groupCopy = fns.assign({}, group);
+    groupCopy.experiments = (group.experiments || []).map(function(experiment) {
+      return fns.assign({}, experiment);
+    });
+    return groupCopy;
+  });
+  datafileCopy.rollouts = (datafile.rollouts || []).map(function(rollout) {
+    var rolloutCopy = fns.assign({}, rollout);
+    rolloutCopy.experiments = (rollout.experiments || []).map(function(experiment) {
+      return fns.assign({}, experiment);
+    });
+    return rolloutCopy;
+  });
+  return datafileCopy;
+}
+
 /**
  * Creates projectConfig object to be used for quick project property lookup
  * @param  {Object} datafile JSON datafile representing the project
  * @return {Object} Object representing project configuration
  */
 export var createProjectConfig = function(datafile) {
-  var projectConfig = fns.assign({}, datafile);
+  var projectConfig = createMutationSafeDatafileCopy(datafile);
 
   /*
    * Conditions of audiences in projectConfig.typedAudiences are not
diff --git a/packages/optimizely-sdk/lib/core/project_config/index.tests.js b/packages/optimizely-sdk/lib/core/project_config/index.tests.js
index a76bdfea4..fadc8a866 100644
--- a/packages/optimizely-sdk/lib/core/project_config/index.tests.js
+++ b/packages/optimizely-sdk/lib/core/project_config/index.tests.js
@@ -33,14 +33,13 @@ import configValidator from '../../utils/config_validator';
 var logger = getLogger();
 
 describe('lib/core/project_config', function() {
-  var parsedAudiences = testDatafile.getParsedAudiences;
   describe('createProjectConfig method', function() {
     it('should set properties correctly when createProjectConfig is called', function() {
       var testData = testDatafile.getTestProjectConfig();
       var configObj = projectConfig.createProjectConfig(testData);
 
       forEach(testData.audiences, function(audience) {
-        audience.conditions = audience.conditions;
+        audience.conditions = JSON.parse(audience.conditions);
       });
 
       assert.strictEqual(configObj.accountId, testData.accountId);
@@ -48,6 +47,12 @@ describe('lib/core/project_config', function() {
       assert.strictEqual(configObj.revision, testData.revision);
       assert.deepEqual(configObj.events, testData.events);
       assert.deepEqual(configObj.audiences, testData.audiences);
+      testData.groups.forEach(function(group) {
+        group.experiments.forEach(function(experiment) {
+          experiment.groupId = group.id;
+          experiment.variationKeyMap = fns.keyBy(experiment.variations, 'key');
+        });
+      });
       assert.deepEqual(configObj.groups, testData.groups);
 
       var expectedGroupIdMap = {
@@ -170,6 +175,13 @@ describe('lib/core/project_config', function() {
       assert.deepEqual(configObj.variationIdMap, expectedVariationIdMap);
     });
 
+    it('should not mutate the datafile', function() {
+      var datafile = testDatafile.getTypedAudiencesConfig();
+      var datafileClone = cloneDeep(datafile);
+      projectConfig.createProjectConfig(datafile);
+      assert.deepEqual(datafileClone, datafile);
+    });
+
     describe('feature management', function() {
       var configObj;
       beforeEach(function() {
diff --git a/packages/optimizely-sdk/lib/optimizely/index.tests.js b/packages/optimizely-sdk/lib/optimizely/index.tests.js
index 917820493..6e9ec01f1 100644
--- a/packages/optimizely-sdk/lib/optimizely/index.tests.js
+++ b/packages/optimizely-sdk/lib/optimizely/index.tests.js
@@ -245,6 +245,28 @@ describe('lib/optimizely', function() {
           });
         });
       });
+
+      it('should support constructing two instances using the same datafile object', function() {
+        var datafile = testData.getTypedAudiencesConfig();
+        var optlyInstance = new Optimizely({
+          clientEngine: 'node-sdk',
+          datafile: datafile,
+          errorHandler: stubErrorHandler,
+          eventDispatcher: stubEventDispatcher,
+          jsonSchemaValidator: jsonSchemaValidator,
+          logger: createdLogger,
+        });
+        assert.instanceOf(optlyInstance, Optimizely);
+        var optlyInstance2 = new Optimizely({
+          clientEngine: 'node-sdk',
+          datafile: datafile,
+          errorHandler: stubErrorHandler,
+          eventDispatcher: stubEventDispatcher,
+          jsonSchemaValidator: jsonSchemaValidator,
+          logger: createdLogger,
+        });
+        assert.instanceOf(optlyInstance2, Optimizely);
+      });
     });
   });