diff --git a/lib/application.js b/lib/application.js
index 0ae50ce..4046a92 100644
--- a/lib/application.js
+++ b/lib/application.js
@@ -51,8 +51,10 @@ Application._createApplication = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(APPLICATION_PATH), {application: item});
-  request.buffer().then(res =>{
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(APPLICATION_PATH), {application: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -64,8 +66,6 @@ Application._createApplication = function(client, item, callback){
     else{
       client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/client.js b/lib/client.js
index a4dbca9..aaada7c 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -41,10 +41,13 @@ class Client {
     
     // Start background token refresh if using OAuth and auto-refresh is enabled
     if (this.autoRefreshToken && this.clientId && this.clientSecret && !this.tempAccessToken) {
-      this.tokenReadyPromise = new Promise((resolve) => {
+      this.tokenReadyPromise = new Promise((resolve, reject) => {
         this._tokenReadyResolve = resolve;
+        this._tokenReadyReject = reject;
       });
-      this._scheduleTokenRefresh();
+      // avoid an unhandled rejection if the fetch fails before any request awaits it
+      this.tokenReadyPromise.catch(() => {});
+      process.nextTick(() => this._refreshToken());
     }
   }
 
@@ -199,52 +202,77 @@ class Client {
     return this.prepareRequest(superagent.del(this.prepareUrl(path)));
   }
 
-  makeRequest (method) {
-    var callback = arguments[arguments.length - 1];
-    var args = Array.prototype.slice.call(arguments, 1, arguments.length - 1);
-    var self = this;
-    
-    const executeRequest = (isRetry = false) => {
-      var request = self["create" + method[0].toUpperCase() + method.substr(1).toLowerCase() + "Request"].apply(self, args);
-      request.buffer().then(res => {
-        self.checkResponse(res, callback);
-      }).catch(err => {
-        // Check for 401 error and no retry yet
-        if (!isRetry && err.status === 401 && self.autoRefreshToken && self.clientId && self.clientSecret) {
-          console.log("Got 401, refreshing token and retrying...");
-          self.tempAccessToken = null;
-          self.tempAccessTokenExpiration = null;
-          
-          self.tokenReadyPromise = new Promise((resolve, reject) => {
-            self._tokenReadyResolve = resolve;
-            self._tokenReadyReject = reject;
-          });
-          self._refreshToken();
-          
-          self.tokenReadyPromise.then(() => {
-            executeRequest(true);
-          }).catch((refreshErr) => {
-            console.error("Token refresh failed during retry:", refreshErr);
-            return callback(err); // Return original 401
-          });
-        } else {
-          return callback(err);
-        }
-      });
+  buildAuthenticatedRequest (buildRequest, callback) {
+    const build = (tokenErr) => {
+      let request;
+      try {
+        request = buildRequest();
+      } catch (err) {
+        return callback(tokenErr || err);
+      }
+      callback(null, request);
     };
-    
+
     if (this.tokenReadyPromise) {
-      this.tokenReadyPromise.then(() => {
-        executeRequest();
-      }).catch((err) => {
+      this.tokenReadyPromise.then(() => build(), (err) => {
         console.error("Token fetch failed:", err);
-        executeRequest();
+        build(err);
       });
     } else {
-      executeRequest();
+      build();
     }
   }
 
+  sendRequest (buildRequest, callback) {
+    const execute = (isRetry) => {
+      this.buildAuthenticatedRequest(buildRequest, (err, request) => {
+        if (err) {
+          return callback(err);
+        }
+        request.buffer().then((res) => callback(null, res), (err) => {
+          if (!isRetry && this._canRefreshOn401(err)) {
+            console.log("Got 401, refreshing token and retrying...");
+            return this._forceTokenRefresh().then(() => execute(true), (refreshErr) => {
+              console.error("Token refresh failed during retry:", refreshErr);
+              callback(err);
+            });
+          }
+          callback(err);
+        });
+      });
+    };
+    execute(false);
+  }
+
+  _canRefreshOn401 (err) {
+    return err.status === 401 && this.autoRefreshToken && this.clientId && this.clientSecret;
+  }
+
+  _forceTokenRefresh () {
+    this.tempAccessToken = null;
+    this.tempAccessTokenExpiration = null;
+    const tokenReadyPromise = new Promise((resolve, reject) => {
+      this._tokenReadyResolve = resolve;
+      this._tokenReadyReject = reject;
+    });
+    this.tokenReadyPromise = tokenReadyPromise;
+    this._refreshToken();
+    return tokenReadyPromise;
+  }
+
+  makeRequest (method) {
+    const callback = arguments[arguments.length - 1];
+    const args = Array.prototype.slice.call(arguments, 1, arguments.length - 1);
+    const createRequest = this["create" + method[0].toUpperCase() + method.substr(1).toLowerCase() + "Request"];
+
+    this.sendRequest(() => createRequest.apply(this, args), (err, res) => {
+      if (err) {
+        return callback(err);
+      }
+      this.checkResponse(res, callback);
+    });
+  }
+
   checkResponse (res, callback) {
     let defaultHandler = function(parsedData){
       if (!res.ok) {
diff --git a/lib/csrOrder.js b/lib/csrOrder.js
index 852afe4..e9c67ba 100644
--- a/lib/csrOrder.js
+++ b/lib/csrOrder.js
@@ -68,8 +68,10 @@ CsrOrder.prototype.getNotes = function(callback){
 
 CsrOrder.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(CSR_ORDER_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res =>{
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(CSR_ORDER_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
diff --git a/lib/disconnect.js b/lib/disconnect.js
index cc4a69c..a8a3cfb 100644
--- a/lib/disconnect.js
+++ b/lib/disconnect.js
@@ -68,8 +68,10 @@ Disconnect.prototype.getNotes = function(callback){
 
 Disconnect.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(DISCONNECT_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res => {
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(DISCONNECT_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -86,8 +88,6 @@ Disconnect.prototype.addNote = function(note, callback){
     else{
       self.client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/dlda.js b/lib/dlda.js
index c05488f..8db46f1 100644
--- a/lib/dlda.js
+++ b/lib/dlda.js
@@ -11,8 +11,10 @@ Dlda.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(DLDA_PATH), {dldaOrder: item});
-  request.buffer().then(res => {
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(DLDA_PATH), {dldaOrder: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err,id){
         if(err){
diff --git a/lib/importTnOrder.js b/lib/importTnOrder.js
index 2def779..975b87b 100644
--- a/lib/importTnOrder.js
+++ b/lib/importTnOrder.js
@@ -79,19 +79,26 @@ function sendFile(request, file, mediaType, callback){
   else if(Buffer.isBuffer(file)){
     stream = streamifier.createReadStream(file);
   }
-  else if(typeof file.pipe === "function" && typeof file.read === "function" && typeof file.on === "function"){
+  else if(file && typeof file.pipe === "function" && typeof file.read === "function" && typeof file.on === "function"){
     stream = file;
   }
-  if(stream){
-    request.on("response", callback);
-    request.on("error", function(err, result){
-      return err;
-    });
-    stream.pipe(request);
-
-    return;
+  if(!stream){
+    return callback(new Error("Invalid data to send"));
   }
-  throw new Error("Invalid data to send");
+  var done = false;
+  // a 4xx/5xx emits "response" then "error"; only report the first
+  var finish = function(err, res){
+    if(!done){
+      done = true;
+      callback(err, res);
+    }
+  };
+  request.on("response", function(res){
+    finish(null, res);
+  });
+  request.on("error", finish);
+  stream.on("error", finish);
+  stream.pipe(request);
 }
 
 ImportTnOrder.prototype.createFile = function(file, mediaType, callback){
@@ -100,18 +107,25 @@ ImportTnOrder.prototype.createFile = function(file, mediaType, callback){
     mediaType = null;
   }
   var client = this.client;
-  var request = client.createPostRequest(client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH));
-  sendFile(request, file, mediaType, function(res){
-    client.checkResponse(res, function(err, result){
+  client.buildAuthenticatedRequest(() => client.createPostRequest(client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH)), function(err, request){
+    if(err){
+      return callback(err);
+    }
+    sendFile(request, file, mediaType, function(err, res){
       if(err){
         return callback(err);
       }
-      if (typeof result !== 'undefined') {
-        return callback(null, result.filename);
-      }
-      else {
-        return callback(null, "");
-      }
+      client.checkResponse(res, function(err, result){
+        if(err){
+          return callback(err);
+        }
+        if (typeof result !== 'undefined') {
+          return callback(null, result.filename);
+        }
+        else {
+          return callback(null, "");
+        }
+      });
     });
   });
 };
@@ -121,10 +135,17 @@ ImportTnOrder.prototype.updateFile = function(fileName, file, mediaType, callbac
     callback = mediaType;
     mediaType = null;
   }
-  var request = this.client.createPutRequest(this.client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
   var client = this.client;
-  sendFile(request, file, mediaType, function(res){
-    client.checkResponse(res, callback);
+  client.buildAuthenticatedRequest(() => client.createPutRequest(client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName)), function(err, request){
+    if(err){
+      return callback(err);
+    }
+    sendFile(request, file, mediaType, function(err, res){
+      if(err){
+        return callback(err);
+      }
+      client.checkResponse(res, callback);
+    });
   });
 };
 
@@ -150,8 +171,25 @@ ImportTnOrder.prototype.getFiles = function(metadata, callback){
   });
 };
 
-ImportTnOrder.prototype.getFile = function(fileName, destination){
-  var request = this.client.createGetRequest(this.client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
+ImportTnOrder.prototype.getFile = function(fileName, destination, callback){
+  if(typeof destination === "function"){
+    callback = destination;
+    destination = null;
+  }
+  var client = this.client;
+  var buildRequest = () => client.createGetRequest(client.concatAccountPath(IMPORT_TN_ORDER_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
+  if(!callback){
+    return pipeToDestination(buildRequest(), destination);
+  }
+  client.buildAuthenticatedRequest(buildRequest, function(err, request){
+    if(err){
+      return callback(err);
+    }
+    callback(null, pipeToDestination(request, destination));
+  });
+}
+
+function pipeToDestination(request, destination){
   if(destination){
     var stream = null;
     if(typeof destination === "string"){
diff --git a/lib/importToAccount.js b/lib/importToAccount.js
index fc54f5c..92588bf 100644
--- a/lib/importToAccount.js
+++ b/lib/importToAccount.js
@@ -13,8 +13,10 @@ ImportToAccount.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(IMPORT_TO_ACCOUNT_PATH), {importToAccountNumberOrder: item});
-  request.buffer().then(res =>{
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(IMPORT_TO_ACCOUNT_PATH), {importToAccountNumberOrder: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok){
       callback(null, res.body)
     }else {
diff --git a/lib/lidbs.js b/lib/lidbs.js
index 5cdf028..df991fa 100644
--- a/lib/lidbs.js
+++ b/lib/lidbs.js
@@ -11,8 +11,10 @@ Lidbs.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(LIDBS_ORDER_PATH), {lidbOrder: item});
-  request.buffer().then(res =>{
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(LIDBS_ORDER_PATH), {lidbOrder: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err,id){
         if(err){
diff --git a/lib/lsrOrder.js b/lib/lsrOrder.js
index 9b1e27d..4220597 100644
--- a/lib/lsrOrder.js
+++ b/lib/lsrOrder.js
@@ -41,8 +41,10 @@ LsrOrder.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(LSR_ORDER_PATH), {lsrOrder: item});
-  request.buffer().then(res => {
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(LSR_ORDER_PATH), {lsrOrder: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err,id){
         if(err){
@@ -83,8 +85,10 @@ LsrOrder.prototype.getNotes = function(callback){
 
 LsrOrder.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(LSR_ORDER_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res =>{
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(LSR_ORDER_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
diff --git a/lib/order.js b/lib/order.js
index 8cf5ec2..cb0779b 100644
--- a/lib/order.js
+++ b/lib/order.js
@@ -117,8 +117,10 @@ Order.prototype.getNotes = function(callback){
 
 Order.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(ORDER_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res => {
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(ORDER_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -135,8 +137,6 @@ Order.prototype.addNote = function(note, callback){
     else{
      self.client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/portIn.js b/lib/portIn.js
index 0a02477..ce0a434 100644
--- a/lib/portIn.js
+++ b/lib/portIn.js
@@ -130,8 +130,10 @@ PortIn.prototype.getNotes = function(callback){
 
 PortIn.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res => {
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -148,8 +150,6 @@ PortIn.prototype.addNote = function(note, callback){
     else{
      self.client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
@@ -172,19 +172,26 @@ function sendFile(request, file, mediaType, callback){
   else if(Buffer.isBuffer(file)){
     stream = streamifier.createReadStream(file);
   }
-  else if(typeof file.pipe === "function" && typeof file.read === "function" && typeof file.on === "function"){
+  else if(file && typeof file.pipe === "function" && typeof file.read === "function" && typeof file.on === "function"){
     stream = file;
   }
-  if(stream){
-    request.on("response", callback);
-    request.on("error", function(err, result){
-      return err;
-    });
-    stream.pipe(request);
-
-    return;
+  if(!stream){
+    return callback(new Error("Invalid data to send"));
   }
-  throw new Error("Invalid data to send");
+  var done = false;
+  // a 4xx/5xx emits "response" then "error"; only report the first
+  var finish = function(err, res){
+    if(!done){
+      done = true;
+      callback(err, res);
+    }
+  };
+  request.on("response", function(res){
+    finish(null, res);
+  });
+  request.on("error", finish);
+  stream.on("error", finish);
+  stream.pipe(request);
 }
 
 PortIn.prototype.createFile = function(file, mediaType, callback){
@@ -193,18 +200,25 @@ PortIn.prototype.createFile = function(file, mediaType, callback){
     mediaType = null;
   }
   var client = this.client;
-  var request = client.createPostRequest(client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH));
-  sendFile(request, file, mediaType, function(res){
-    client.checkResponse(res, function(err, result){
+  client.buildAuthenticatedRequest(() => client.createPostRequest(client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH)), function(err, request){
+    if(err){
+      return callback(err);
+    }
+    sendFile(request, file, mediaType, function(err, res){
       if(err){
         return callback(err);
       }
-      if (typeof result !== 'undefined') {
-        return callback(null, result.filename);
-      }
-      else {
-        return callback(null, "");
-      }
+      client.checkResponse(res, function(err, result){
+        if(err){
+          return callback(err);
+        }
+        if (typeof result !== 'undefined') {
+          return callback(null, result.filename);
+        }
+        else {
+          return callback(null, "");
+        }
+      });
     });
   });
 };
@@ -214,10 +228,17 @@ PortIn.prototype.updateFile = function(fileName, file, mediaType, callback){
     callback = mediaType;
     mediaType = null;
   }
-  var request = this.client.createPutRequest(this.client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
   var client = this.client;
-  sendFile(request, file, mediaType, function(res){
-    client.checkResponse(res, callback);
+  client.buildAuthenticatedRequest(() => client.createPutRequest(client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName)), function(err, request){
+    if(err){
+      return callback(err);
+    }
+    sendFile(request, file, mediaType, function(err, res){
+      if(err){
+        return callback(err);
+      }
+      client.checkResponse(res, callback);
+    });
   });
 };
 
@@ -243,8 +264,25 @@ PortIn.prototype.getFiles = function(metadata, callback){
   });
 };
 
-PortIn.prototype.getFile = function(fileName, destination){
-  var request = this.client.createGetRequest(this.client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
+PortIn.prototype.getFile = function(fileName, destination, callback){
+  if(typeof destination === "function"){
+    callback = destination;
+    destination = null;
+  }
+  var client = this.client;
+  var buildRequest = () => client.createGetRequest(client.concatAccountPath(PORT_IN_PATH + "/" + this.id + "/" + LOAS_PATH + "/" + fileName));
+  if(!callback){
+    return pipeToDestination(buildRequest(), destination);
+  }
+  client.buildAuthenticatedRequest(buildRequest, function(err, request){
+    if(err){
+      return callback(err);
+    }
+    callback(null, pipeToDestination(request, destination));
+  });
+}
+
+function pipeToDestination(request, destination){
   if(destination){
     var stream = null;
     if(typeof destination === "string"){
diff --git a/lib/portOut.js b/lib/portOut.js
index cc86318..91b63b3 100644
--- a/lib/portOut.js
+++ b/lib/portOut.js
@@ -49,8 +49,10 @@ PortOut.prototype.getNotes = function(callback){
 
 PortOut.prototype.addNote = function(note, callback){
   var self = this;
-  var request = this.client.createPostRequest(this.client.concatAccountPath(PORT_OUT_PATH + "/" + this.id + "/notes"), {note: note});
-  request.buffer().then(res =>{
+  this.client.sendRequest(() => this.client.createPostRequest(this.client.concatAccountPath(PORT_OUT_PATH + "/" + this.id + "/notes"), {note: note}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -67,8 +69,6 @@ PortOut.prototype.addNote = function(note, callback){
     else{
       self.client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/site.js b/lib/site.js
index 7aeb26d..c2d3055 100644
--- a/lib/site.js
+++ b/lib/site.js
@@ -52,8 +52,10 @@ Site.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(SITE_PATH), {site: item});
-  request.buffer().then(res =>{
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(SITE_PATH), {site: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -65,8 +67,6 @@ Site.create = function(client, item, callback){
     else{
       client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
@@ -123,8 +123,10 @@ Site.prototype.getSipPeer = function(id, callback){
 Site.prototype.createSipPeer = function(item, callback){
   var client = this.client;
   var self = this;
-  var request = client.createPostRequest( this.client.concatAccountPath(SITE_PATH) + "/" + this.id + "/" + SIP_PEER_PATH, {sipPeer: item});
-  request.buffer().then(res =>{
+  client.sendRequest(() => client.createPostRequest(this.client.concatAccountPath(SITE_PATH) + "/" + this.id + "/" + SIP_PEER_PATH, {sipPeer: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -136,8 +138,6 @@ Site.prototype.createSipPeer = function(item, callback){
     else{
       client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/subscription.js b/lib/subscription.js
index c808e30..5f93763 100644
--- a/lib/subscription.js
+++ b/lib/subscription.js
@@ -57,8 +57,10 @@ Subscription.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(SUBSCRIPTION_PATH), {subscription: item});
-  request.buffer().then(res => {
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(SUBSCRIPTION_PATH), {subscription: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -70,8 +72,6 @@ Subscription.create = function(client, item, callback){
     else{
       client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/lib/tnOption.js b/lib/tnOption.js
index cc50165..085a76f 100644
--- a/lib/tnOption.js
+++ b/lib/tnOption.js
@@ -61,7 +61,6 @@ TnOption.create = function(client, order, callback){
     group.telephoneNumbers = {telephoneNumber: group.telephoneNumbers}
   });
 
-  var request = client.createPostRequest(client.concatAccountPath(TN_OPTION_PATH), {tnOptionOrder: order});
   client.makeRequest("post", client.concatAccountPath(TN_OPTION_PATH), {tnOptionOrder: order}, function(err, item){
    if(err){
      return callback(err);
diff --git a/lib/tnReservation.js b/lib/tnReservation.js
index 107f2d2..627eb08 100644
--- a/lib/tnReservation.js
+++ b/lib/tnReservation.js
@@ -29,8 +29,10 @@ TnReservation.create = function(client, item, callback){
     item = client;
     client = new Client();
   }
-  var request = client.createPostRequest(client.concatAccountPath(TN_RESERVATION_PATH), {reservation: item});
-  request.buffer().then(res => {
+  client.sendRequest(() => client.createPostRequest(client.concatAccountPath(TN_RESERVATION_PATH), {reservation: item}), function(err, res){
+    if(err){
+      return callback(err);
+    }
     if(res.ok && res.headers.location){
       Client.getIdFromLocationHeader(res.headers.location, function(err, id){
         if(err){
@@ -42,8 +44,6 @@ TnReservation.create = function(client, item, callback){
     else{
       client.checkResponse(res, callback);
     }
-  }).catch(err => {
-    return callback(err);
   });
 };
 
diff --git a/test/client.js b/test/client.js
index b3f4aeb..5b224cf 100644
--- a/test/client.js
+++ b/test/client.js
@@ -418,6 +418,81 @@ describe("client tests", function(){
       });
     })
   });
+  describe("OAuth token handling", function(){
+    var client;
+    afterEach(function(){
+      client.destroy();
+      nock.cleanAll();
+    });
+    it("should wait for the token before making a request", function(done){
+      helper.nockToken().reply(200, {access_token: "fake_token", expires_in: 3600});
+      helper.nock().matchHeader("authorization", "Bearer fake_token").get("/test")
+        .reply(200, "<Response><Test>test</Test></Response>", {"Content-Type": "application/xml"});
+      client = helper.createOAuthClient();
+      client.makeRequest("get", "/test", function(err, r){
+        if(err){
+          return done(err);
+        }
+        r.test.should.equal("test");
+        done();
+      });
+    });
+    it("should fail with the token error if token fetch fails and no other auth is available", function(done){
+      helper.nockToken().reply(401);
+      client = helper.createOAuthClient();
+      client.makeRequest("get", "/test", function(err){
+        if(!err){
+          return done(new Error("An error is expected"));
+        }
+        err.status.should.equal(401);
+        done();
+      });
+    });
+    it("should fall back to basic auth if token fetch fails", function(done){
+      helper.nockToken().reply(401);
+      helper.nock().matchHeader("authorization", /^Basic /).get("/test").reply(200);
+      client = new Client("FakeAccountId", "FakeUserName", "FakePassword", "FakeClientId", "FakeClientSecret");
+      client.makeRequest("get", "/test", done);
+    });
+    it("should refresh the token and retry once on 401", function(done){
+      helper.nockToken().reply(200, {access_token: "expired_token", expires_in: 3600});
+      helper.nockToken().reply(200, {access_token: "fresh_token", expires_in: 3600});
+      helper.nock().matchHeader("authorization", "Bearer expired_token").get("/test").reply(401);
+      helper.nock().matchHeader("authorization", "Bearer fresh_token").get("/test")
+        .reply(200, "<Response><Test>test</Test></Response>", {"Content-Type": "application/xml"});
+      client = helper.createOAuthClient();
+      client.makeRequest("get", "/test", function(err, r){
+        if(err){
+          return done(err);
+        }
+        r.test.should.equal("test");
+        done();
+      });
+    });
+    it("should not retry more than once on 401", function(done){
+      helper.nockToken().times(2).reply(200, {access_token: "fake_token", expires_in: 3600});
+      helper.nock().get("/test").times(2).reply(401);
+      client = helper.createOAuthClient();
+      client.makeRequest("get", "/test", function(err){
+        if(!err){
+          return done(new Error("An error is expected"));
+        }
+        err.status.should.equal(401);
+        done();
+      });
+    });
+  });
+  describe("#buildAuthenticatedRequest", function(){
+    it("should pass auth errors to the callback instead of throwing", function(done){
+      var client = new Client("FakeAccountId", null, null, null, null);
+      client.buildAuthenticatedRequest(function(){
+        return client.createGetRequest("/test");
+      }, function(err){
+        err.message.should.equal("No authentication method available");
+        done();
+      });
+    });
+  });
   describe("#concatAccountPath", function(){
     it("should return formatted url", function(){
       var client = new Client("accountId");
diff --git a/test/dlda.js b/test/dlda.js
index bbb337e..fe61f03 100644
--- a/test/dlda.js
+++ b/test/dlda.js
@@ -53,6 +53,15 @@ describe("Dlda", function(){
         done();
       });
     });
+    it("should fail on error status code", function(done){
+      helper.nock().post("/accounts/FakeAccountId/dldas").reply(400);
+      Dlda.create(helper.createClient(), {}, function(err){
+        if(err){
+          return done();
+        }
+        done(new Error("An error is expected"));
+      });
+    });
   });
   describe("#getHistory", function(){
     it("should return history", function(done){
diff --git a/test/helper.js b/test/helper.js
index ee1b6f3..7e1f00b 100644
--- a/test/helper.js
+++ b/test/helper.js
@@ -12,6 +12,14 @@ module.exports = {
     return new Client("FakeAccountId", "FakeUserName", "FakePassword");
   },
 
+  createOAuthClient: function(){
+    return new Client("FakeAccountId", null, null, "FakeClientId", "FakeClientSecret");
+  },
+
+  nockToken: function(){
+    return nock("https://api.bandwidth.com").post("/api/v1/oauth2/token", "grant_type=client_credentials");
+  },
+
   buildXml: function(obj){
     return this.createClient().buildXml(obj);
   },
diff --git a/test/portIn.js b/test/portIn.js
index 449a42a..a158e95 100644
--- a/test/portIn.js
+++ b/test/portIn.js
@@ -388,6 +388,42 @@ describe("PortIn", function(){
         });
       });
     });
+    it("should download file to destination file via callback with OAuth client credentials only", function(done){
+      nock.cleanAll();
+      helper.nockToken().reply(200, {access_token: "fake_token", expires_in: 3600});
+      helper.nock().matchHeader("authorization", "Bearer fake_token").get("/accounts/FakeAccountId/portins/1/loas/file.txt").reply(200, "12345", {"Content-Type": "text/plain"});
+      var order = new PortIn();
+      order.id = 1;
+      order.client = helper.createOAuthClient();
+      order.getFile("file.txt", tmpFile, function(err, stream){
+        if(err){
+          return done(err);
+        }
+        stream.on("finish", function(){
+          order.client.destroy();
+          fs.readFile(tmpFile, "utf8", function(err, text){
+            if(err){
+              done(err);
+            }
+            text.should.equal("12345");
+            done();
+          });
+        });
+      });
+    });
+    it("should fail via callback if no auth method available", function(done){
+      fs.writeFileSync(tmpFile, "");
+      var order = new PortIn();
+      order.id = 1;
+      order.client = new lib.Client("FakeAccountId", null, null, null, null);
+      order.getFile("file.txt", function(err){
+        if(err){
+          err.message.should.equal("No authentication method available");
+          return done();
+        }
+        done(new Error("An error was expected"));
+      });
+    });
   });
   describe("#createFile", function(){
     var order, tmpFile = path.join(os.tmpdir(), "dest.txt");
@@ -450,6 +486,40 @@ describe("PortIn", function(){
         done();
       });
     });
+    it("should upload file to the server with OAuth client credentials only", function(done){
+      nock.cleanAll();
+      helper.nockToken().reply(200, {access_token: "fake_token", expires_in: 3600});
+      helper.nock().matchHeader("authorization", "Bearer fake_token").post("/accounts/FakeAccountId/portins/1/loas", "12345").reply(200, helper.xml.fileCreated, {"Content-Type": "application/xml"});
+      order.client = helper.createOAuthClient();
+      order.createFile(new Buffer.from("12345", "utf8"), "text/plain", function(err, fileName){
+        order.client.destroy();
+        if(err){
+          return done(err);
+        }
+        fileName.should.equal("test.txt");
+        done();
+      });
+    });
+    it("should fail on invalid data", function(done){
+      order.createFile(12345, "text/plain", function(err){
+        if(err){
+          err.message.should.equal("Invalid data to send");
+          return done();
+        }
+        done(new Error("An error was expected"));
+      });
+    });
+    it("should fail on network error", function(done){
+      nock.cleanAll();
+      helper.nock().post("/accounts/FakeAccountId/portins/1/loas").replyWithError({code: "ECONNRESET", message: "socket hang up"});
+      order.createFile(new Buffer.from("12345", "utf8"), "text/plain", function(err){
+        if(err){
+          err.code.should.equal("ECONNRESET");
+          return done();
+        }
+        done(new Error("An error was expected"));
+      });
+    });
   });
   describe("#updateFile", function(){
     var order, tmpFile = path.join(os.tmpdir(), "dest.txt");
diff --git a/test/tnOption.js b/test/tnOption.js
index 89ded82..6b5d62f 100644
--- a/test/tnOption.js
+++ b/test/tnOption.js
@@ -221,5 +221,28 @@ describe("TnOption", function(){
         done(new Error("An error is expected"));
       });
     });
+
+    it("should create with OAuth client credentials only", function(done){
+      const userInput = {
+        customerOrderId: 'myOrderId',
+        tnOptionGroups: [
+          {
+            sms: 'on',
+            telephoneNumbers: ['2018551020']
+          }
+        ]
+      }
+      const client = helper.createOAuthClient();
+      helper.nockToken().reply(200, {access_token: "fake_token", expires_in: 3600});
+      helper.nock().matchHeader("authorization", "Bearer fake_token").post("/accounts/FakeAccountId/tnoptions").reply(201, helper.xml.tnOptionOrderResponse, {"Location": "/accounts/FakeAccountId/tnoptions/1"});
+      TnOption.create(client, userInput,  function(err, item){
+        client.destroy();
+        if(err){
+          return done(err);
+        }
+        item.createdByUser.should.equal('user');
+        done();
+      });
+    });
   });
 });