diff --git a/src/txacme/challenges/__init__.py b/src/txacme/challenges/__init__.py
index 61bb835..af6cb85 100644
--- a/src/txacme/challenges/__init__.py
+++ b/src/txacme/challenges/__init__.py
@@ -1,3 +1,4 @@
+from ._http import HTTP01Responder
 from ._tls import TLSSNI01Responder
 
-__all__ = ['TLSSNI01Responder']
+__all__ = ['HTTP01Responder', 'TLSSNI01Responder']
diff --git a/src/txacme/challenges/_http.py b/src/txacme/challenges/_http.py
new file mode 100644
index 0000000..70f4046
--- /dev/null
+++ b/src/txacme/challenges/_http.py
@@ -0,0 +1,39 @@
+"""
+``http-01`` challenge implementation.
+"""
+from twisted.web.resource import Resource
+from twisted.web.static import Data
+
+from zope.interface import implementer
+
+from txacme.interfaces import IResponder
+
+
+@implementer(IResponder)
+class HTTP01Responder(object):
+    """
+    An ``http-01`` challenge responder for txsni.
+    """
+    challenge_type = u'http-01'
+
+    def __init__(self):
+        self.resource = Resource()
+
+    def start_responding(self, server_name, challenge, response):
+        """
+        Add the child resource.
+        """
+        self.resource.putChild(
+            challenge.encode('token').encode('utf-8'),
+            Data(response.key_authorization.encode('utf-8'), 'text/plain'))
+
+    def stop_responding(self, server_name, challenge, response):
+        """
+        Remove the child resource.
+        """
+        encoded_token = challenge.encode('token').encode('utf-8')
+        if self.resource.getStaticEntity(encoded_token) is not None:
+            self.resource.delEntity(encoded_token)
+
+
+__all__ = ['HTTP01Responder']
diff --git a/src/txacme/newsfragments/65.feature b/src/txacme/newsfragments/65.feature
new file mode 100644
index 0000000..4e7f84c
--- /dev/null
+++ b/src/txacme/newsfragments/65.feature
@@ -0,0 +1 @@
+``txacme.challenges.HTTP01Responder``, an http-01 challenge responder that can be embedded into an existing twisted.web application.
diff --git a/src/txacme/test/test_challenges.py b/src/txacme/test/test_challenges.py
index a73a8ba..b5afd3f 100644
--- a/src/txacme/test/test_challenges.py
+++ b/src/txacme/test/test_challenges.py
@@ -1,15 +1,23 @@
 """
 Tests for `txacme.challenges`.
 """
+from operator import methodcaller
+
 from acme import challenges
 from acme.jose import b64encode
 from hypothesis import strategies as s
 from hypothesis import example, given
 from testtools import TestCase
-from testtools.matchers import Contains, Equals, Is, MatchesPredicate, Not
+from testtools.matchers import (
+    AfterPreprocessing, Contains, Equals, Is, MatchesAll, MatchesPredicate,
+    MatchesStructure, Not)
+from testtools.twistedsupport import succeeded
+from treq.testing import StubTreq
+from twisted.python.url import URL
+from twisted.web.resource import Resource
 from zope.interface.verify import verifyObject
 
-from txacme.challenges import TLSSNI01Responder
+from txacme.challenges import HTTP01Responder, TLSSNI01Responder
 from txacme.challenges._tls import _MergingMappingProxy
 from txacme.interfaces import IResponder
 from txacme.test.test_client import RSA_KEY_512, RSA_KEY_512_RAW
@@ -172,4 +180,57 @@ def test_contains(self, underlay, overlay, key):
             Equals(proxy.get(key) is not None))
 
 
-__all__ = ['TLSResponderTests']
+class HTTPResponderTests(_CommonResponderTests, TestCase):
+    """
+    `.HTTP01Responder` is a responder for http-01 challenges.
+    """
+    _challenge_factory = challenges.HTTP01
+    _responder_factory = HTTP01Responder
+    _challenge_type = u'http-01'
+
+    @example(token=b'BWYcfxzmOha7-7LoxziqPZIUr99BCz3BfbN9kzSFnrU')
+    @given(token=s.binary(min_size=32, max_size=32).map(b64encode))
+    def test_start_responding(self, token):
+        """
+        Calling ``start_responding`` makes an appropriate resource available.
+        """
+        challenge = challenges.HTTP01(token=token)
+        response = challenge.response(RSA_KEY_512)
+
+        responder = HTTP01Responder()
+
+        challenge_resource = Resource()
+        challenge_resource.putChild(b'acme-challenge', responder.resource)
+        root = Resource()
+        root.putChild(b'.well-known', challenge_resource)
+        client = StubTreq(root)
+
+        encoded_token = challenge.encode('token')
+        challenge_url = URL(host=u'example.com', path=[
+            u'.well-known', u'acme-challenge', encoded_token]).asText()
+
+        self.assertThat(client.get(challenge_url),
+                        succeeded(MatchesStructure(code=Equals(404))))
+
+        responder.start_responding(u'example.com', challenge, response)
+        self.assertThat(client.get(challenge_url), succeeded(MatchesAll(
+            MatchesStructure(
+                code=Equals(200),
+                headers=AfterPreprocessing(
+                    methodcaller('getRawHeaders', b'content-type'),
+                    Equals([b'text/plain']))),
+            AfterPreprocessing(methodcaller('content'), succeeded(
+                Equals(response.key_authorization.encode('utf-8'))))
+        )))
+
+        # Starting twice before stopping doesn't break things
+        responder.start_responding(u'example.com', challenge, response)
+        self.assertThat(client.get(challenge_url),
+                        succeeded(MatchesStructure(code=Equals(200))))
+
+        responder.stop_responding(u'example.com', challenge, response)
+        self.assertThat(client.get(challenge_url),
+                        succeeded(MatchesStructure(code=Equals(404))))
+
+
+__all__ = ['HTTPResponderTests', 'TLSResponderTests']