diff --git a/benchmark/addressbook.capnp.bytes.py b/benchmark/addressbook.capnp.bytes.py
new file mode 100644
index 0000000..2f126e3
--- /dev/null
+++ b/benchmark/addressbook.capnp.bytes.py
@@ -0,0 +1,54 @@
+from __future__ import print_function
+import os
+import capnp
+
+this_dir = os.path.dirname(__file__)
+addressbook = capnp.load(os.path.join(this_dir, 'addressbook.capnp'))
+
+print = lambda *x: x
+
+
+def writeAddressBook(f):
+    addressBook = addressbook.AddressBook.new_message()
+    people = addressBook.init('people', 2)
+
+    alice = people[0]
+    alice.id = 123
+    alice.name = 'Alice'
+    alice.email = 'alice@example.com'
+    alicePhones = alice.init('phones', 1)
+    alicePhones[0].number = "555-1212"
+    alicePhones[0].type = 'mobile'
+
+    bob = people[1]
+    bob.id = 456
+    bob.name = 'Bob'
+    bob.email = 'bob@example.com'
+    bobPhones = bob.init('phones', 2)
+    bobPhones[0].number = "555-4567"
+    bobPhones[0].type = 'home'
+    bobPhones[1].number = "555-7654"
+    bobPhones[1].type = 'work'
+
+    msg_bytes = addressBook.to_bytes()
+    f.write(msg_bytes)
+
+def printAddressBook(msg_bytes):
+    addressBook = addressbook.AddressBook.from_bytes(msg_bytes)
+
+    for person in addressBook.people:
+        print(person.name, ':', person.email)
+        for phone in person.phones:
+            print(phone.type, ':', phone.number)
+        print()
+
+
+if __name__ == '__main__':
+    for i in range(10000):
+        f = open('example', 'w')
+        writeAddressBook(f)
+
+        f = open('example', 'r')
+        printAddressBook(f.read())
+
+os.remove('example')
diff --git a/benchmark/addressbook.capnp.py b/benchmark/addressbook.capnp.py
index 8fb91f1..8d0cdf3 100644
--- a/benchmark/addressbook.capnp.py
+++ b/benchmark/addressbook.capnp.py
@@ -8,9 +8,8 @@ addressbook = capnp.load(os.path.join(this_dir, 'addressbook.capnp'))
 print = lambda *x: x
 
 
-def writeAddressBook(fd):
-    message = capnp.MallocMessageBuilder()
-    addressBook = message.initRoot(addressbook.AddressBook)
+def writeAddressBook(f):
+    addressBook = addressbook.AddressBook.new_message()
     people = addressBook.init('people', 2)
 
     alice = people[0]
@@ -31,12 +30,11 @@ def writeAddressBook(fd):
     bobPhones[1].number = "555-7654"
     bobPhones[1].type = 'work'
 
-    capnp.writePackedMessageToFd(fd, message)
+    addressBook.write(f)
 
 
-def printAddressBook(fd):
-    message = capnp.PackedFdMessageReader(f.fileno())
-    addressBook = message.getRoot(addressbook.AddressBook)
+def printAddressBook(f):
+    addressBook = addressbook.AddressBook.read(f)
 
     for person in addressBook.people:
         print(person.name, ':', person.email)
@@ -48,9 +46,9 @@ def printAddressBook(fd):
 if __name__ == '__main__':
     for i in range(10000):
         f = open('example', 'w')
-        writeAddressBook(f.fileno())
+        writeAddressBook(f)
 
         f = open('example', 'r')
-        printAddressBook(f.fileno())
+        printAddressBook(f)
 
 os.remove('example')