diff --git a/netlib/websockets.py b/netlib/websockets.py
index 016e75c2b..b1afa6206 100644
--- a/netlib/websockets.py
+++ b/netlib/websockets.py
@@ -115,6 +115,8 @@ def create_server_nonce(client_nonce):
 
 
 DEFAULT = object()
+
+
 class FrameHeader:
     def __init__(
         self,
@@ -128,6 +130,8 @@ class FrameHeader:
         mask = DEFAULT,
         length_code = DEFAULT
     ):
+        if not 0 <= opcode < 2 ** 4:
+            raise ValueError("opcode must be 0-16")
         self.opcode = opcode
         self.payload_length = payload_length
         self.fin = fin
@@ -275,26 +279,6 @@ class Frame(object):
             masking_key = masking_key,
         )
 
-    def is_valid(self):
-        """
-            Validate websocket frame invariants, call at anytime to ensure the
-            Frame has not been corrupted.
-        """
-        constraints = [
-            0 <= self.header.fin <= 1,
-            0 <= self.header.rsv1 <= 1,
-            0 <= self.header.rsv2 <= 1,
-            0 <= self.header.rsv3 <= 1,
-            1 <= self.header.opcode <= 4,
-            0 <= self.header.mask <= 1,
-            #1 <= self.payload_length_code <= 127,
-            1 <= len(self.header.masking_key) <= 4 if self.header.mask else True,
-            self.header.masking_key is not None if self.header.mask else True
-        ]
-        if not all(constraints):
-            return False
-        return True
-
     def human_readable(self):
         return "\n".join([
             ("fin                   - " + str(self.header.fin)),
diff --git a/test/test_websockets.py b/test/test_websockets.py
index 06876e0b8..215b39581 100644
--- a/test/test_websockets.py
+++ b/test/test_websockets.py
@@ -4,6 +4,7 @@ import os
 from nose.tools import raises
 
 from netlib import tcp, test, websockets, http
+import tutils
 
 
 class WebSocketsEchoHandler(tcp.BaseHandler):
@@ -106,25 +107,7 @@ class TestWebSockets(test.ServerTestBase):
         """
         msg = self.random_bytes()
         client_frame = websockets.Frame.default(msg, from_client = True)
-
         server_frame = websockets.Frame.default(msg, from_client = False)
-        assert server_frame.is_valid()
-
-    def test_is_valid(self):
-        def f():
-            return websockets.Frame.default(self.random_bytes(10), True)
-
-        frame = f()
-        assert frame.is_valid()
-
-        frame = f()
-        frame.header.fin = 2
-        assert not frame.is_valid()
-
-        frame = f()
-        frame.header.mask_bit = 1
-        frame.header.masking_key = "foobbarboo"
-        assert not frame.is_valid()
 
     def test_serialization_bijection(self):
         """
@@ -207,6 +190,9 @@ class TestFrameHeader:
         f2 = websockets.FrameHeader.from_file(cStringIO.StringIO(bytes))
         assert not f2.mask
 
+    def test_violations(self):
+        tutils.raises("opcode", websockets.FrameHeader, opcode=17)
+
 
 class TestFrame:
     def test_roundtrip(self):
@@ -216,3 +202,7 @@ class TestFrame:
             f2 = websockets.Frame.from_file(cStringIO.StringIO(bytes))
             assert f == f2
         round("test")
+
+    def test_human_readable(self):
+        f = websockets.Frame()
+        assert f.human_readable()