diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cae14c013..e14268f23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,6 +6,10 @@ on:
       - "master"
   pull_request:
 
+env:
+  # Tell Hypothesis which configuration we want it to use.
+  TAHOE_LAFS_HYPOTHESIS_PROFILE: "ci"
+
 jobs:
 
   coverage:
diff --git a/newsfragments/3615.minor b/newsfragments/3615.minor
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index 51496537a..38598fe9b 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -117,6 +117,10 @@ PORTED_MODULES = [
     "allmydata.util.statistics",
     "allmydata.util.time_format",
     "allmydata.web.common",
+    "allmydata.web.check_results",
+    "allmydata.web.filenode",
+    "allmydata.web.info",
+    "allmydata.web.introweb",
     "allmydata.web.logs",
     "allmydata.webish",
 ]
diff --git a/src/allmydata/web/check_results.py b/src/allmydata/web/check_results.py
index 1bf726fb2..6c8810f2b 100644
--- a/src/allmydata/web/check_results.py
+++ b/src/allmydata/web/check_results.py
@@ -1,4 +1,14 @@
-from future.builtins import str
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import time
 
diff --git a/src/allmydata/web/filenode.py b/src/allmydata/web/filenode.py
index 9929a6236..dd793888e 100644
--- a/src/allmydata/web/filenode.py
+++ b/src/allmydata/web/filenode.py
@@ -1,4 +1,18 @@
-from past.builtins import unicode, long
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, max, min  # noqa: F401
+    # Use native unicode() as str() to prevent leaking futurebytes in ways that
+    # break string formattin.
+    from past.builtins import unicode as str
+from past.builtins import long
 
 from twisted.web import http, static
 from twisted.internet import defer
@@ -130,7 +144,7 @@ class PlaceHolderNodeHandler(Resource, ReplaceMeMixin):
         if t == b"uri":
             return self.replace_me_with_a_childcap(req, self.client, replace)
 
-        raise WebError("PUT to a file: bad t=%s" % unicode(t, "utf-8"))
+        raise WebError("PUT to a file: bad t=%s" % str(t, "utf-8"))
 
     @render_exception
     def render_POST(self, req):
@@ -147,7 +161,7 @@ class PlaceHolderNodeHandler(Resource, ReplaceMeMixin):
             # t=mkdir is handled in DirectoryNodeHandler._POST_mkdir, so
             # there are no other t= values left to be handled by the
             # placeholder.
-            raise WebError("POST to a file: bad t=%s" % unicode(t, "utf-8"))
+            raise WebError("POST to a file: bad t=%s" % str(t, "utf-8"))
 
         return handle_when_done(req, d)
 
@@ -180,7 +194,7 @@ class FileNodeHandler(Resource, ReplaceMeMixin, object):
 
     @render_exception
     def render_GET(self, req):
-        t = unicode(get_arg(req, b"t", b"").strip(), "ascii")
+        t = str(get_arg(req, b"t", b"").strip(), "ascii")
 
         # t=info contains variable ophandles, so is not allowed an ETag.
         FIXED_OUTPUT_TYPES = ["", "json", "uri", "readonly-uri"]
@@ -287,7 +301,7 @@ class FileNodeHandler(Resource, ReplaceMeMixin, object):
             assert self.parentnode and self.name
             return self.replace_me_with_a_childcap(req, self.client, replace)
 
-        raise WebError("PUT to a file: bad t=%s" % unicode(t, "utf-8"))
+        raise WebError("PUT to a file: bad t=%s" % str(t, "utf-8"))
 
     @render_exception
     def render_POST(self, req):
@@ -309,7 +323,7 @@ class FileNodeHandler(Resource, ReplaceMeMixin, object):
                 assert self.parentnode and self.name
                 d = self.replace_me_with_a_formpost(req, self.client, replace)
         else:
-            raise WebError("POST to file: bad t=%s" % unicode(t, "ascii"))
+            raise WebError("POST to file: bad t=%s" % str(t, "ascii"))
 
         return handle_when_done(req, d)
 
@@ -374,7 +388,7 @@ class FileDownloader(Resource, object):
         self.filenode = filenode
         self.filename = filename
 
-    def parse_range_header(self, range):
+    def parse_range_header(self, range_header):
         # Parse a byte ranges according to RFC 2616 "14.35.1 Byte
         # Ranges".  Returns None if the range doesn't make sense so it
         # can be ignored (per the spec).  When successful, returns a
@@ -385,7 +399,7 @@ class FileDownloader(Resource, object):
 
         try:
             # byte-ranges-specifier
-            units, rangeset = range.split('=', 1)
+            units, rangeset = range_header.split('=', 1)
             if units != 'bytes':
                 return None     # nothing else supported
 
diff --git a/src/allmydata/web/info.py b/src/allmydata/web/info.py
index 21ac0fd7e..2d45f9994 100644
--- a/src/allmydata/web/info.py
+++ b/src/allmydata/web/info.py
@@ -1,4 +1,14 @@
-from past.builtins import unicode
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import os
 from urllib.parse import quote as urlquote
@@ -47,7 +57,7 @@ class MoreInfoElement(Element):
 
     def abbrev(self, storage_index_or_none):
         if storage_index_or_none:
-            return unicode(base32.b2a(storage_index_or_none)[:6], "ascii")
+            return str(base32.b2a(storage_index_or_none)[:6], "ascii")
         return "LIT file"
 
     def get_type(self):
diff --git a/src/allmydata/web/introweb.py b/src/allmydata/web/introweb.py
index 280d6cc26..621a15a5c 100644
--- a/src/allmydata/web/introweb.py
+++ b/src/allmydata/web/introweb.py
@@ -1,3 +1,14 @@
+"""
+Ported to Python 3.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import time, os
 from pkg_resources import resource_filename