diff --git a/activitypub/__init__.py b/activitypub/__init__.py
index 91f3aae..45b03e2 100644
--- a/activitypub/__init__.py
+++ b/activitypub/__init__.py
@@ -1,3 +1,2 @@
-from .manager import Manager
 from .classes import *
 from ._version import __version__, VERSION
diff --git a/activitypub/bson/objectid.py b/activitypub/bson/objectid.py
index 4be91c3..4d63c01 100644
--- a/activitypub/bson/objectid.py
+++ b/activitypub/bson/objectid.py
@@ -147,7 +147,7 @@ class ObjectId(object):
         >>> import datetime
         >>> gen_time = datetime.datetime(2010, 1, 1)
         >>> early = ObjectId.from_datetime(gen_time)
-        >>> from activitypub import Manager
+        >>> from activitypub.manager import Manager
         >>> from activitypub.database import DummyDatabase
         >>> m = Manager(database=DummyDatabase())
         >>> n = m.Note(_id=early, attributedTo="alyssa")
diff --git a/activitypub/classes.py b/activitypub/classes.py
index 3376d66..e5a47d6 100644
--- a/activitypub/classes.py
+++ b/activitypub/classes.py
@@ -46,12 +46,12 @@ class ActivityPubBase():
                 if attr is None:
                     raise Exception("variable depends on field that is empty: %s" % attr_name)
                 if isinstance(attr, str) and "$" in attr:
-                    setattr(self, attr_name, self.manager.expand_defaults(attr))
+                    setattr(self, attr_name, self.manager.expand_defaults(attr, self))
 
     def topological_sort(self, data):
         """
 
-        >>> from activitypub import Manager
+        >>> from activitypub.manager import Manager
         >>> manager = Manager()
         >>> manager.Person(id="alyssa").to_dict()
         {'@context': 'https://www.w3.org/ns/activitystreams', 'endpoints': {}, 'followers': 'https://example.com/alyssa/followers', 'following': 'https://example.com/alyssa/following', 'id': 'https://example.com/alyssa', 'inbox': 'https://example.com/alyssa/inbox', 'liked': 'https://example.com/alyssa/liked', 'likes': 'https://example.com/alyssa/likes', 'outbox': 'https://example.com/alyssa/outbox', 'type': 'Person', 'url': 'https://example.com/alyssa'}
@@ -184,7 +184,7 @@ class Organization(Actor):
 
 class Person(Actor):
     """
-    >>> from activitypub import Manager
+    >>> from activitypub.manager import Manager
     >>> m = Manager()
     >>> p = m.Person()
     >>> p.icon = "image.svg"
diff --git a/activitypub/manager/__init__.py b/activitypub/manager/__init__.py
new file mode 100644
index 0000000..cb894b0
--- /dev/null
+++ b/activitypub/manager/__init__.py
@@ -0,0 +1,4 @@
+
+from .base import Manager
+from .flaskman import FlaskManager
+from .tornadoman import TornadoManager
diff --git a/activitypub/manager.py b/activitypub/manager/base.py
similarity index 77%
rename from activitypub/manager.py
rename to activitypub/manager/base.py
index dbaee1a..cb33be1 100644
--- a/activitypub/manager.py
+++ b/activitypub/manager/base.py
@@ -1,3 +1,5 @@
+import binascii
+import os
 import uuid
 
 class Manager():
@@ -5,7 +7,7 @@ class Manager():
     Manager class that ties together ActivityPub objects, defaults,
     and a database.
 
-    >>> from activitypub import Manager
+    >>> from activitypub.manager import Manager
     >>> from activitypub.database import DummyDatabase
     >>> db = DummyDatabase()
     >>> manager = Manager(database=db)
@@ -14,7 +16,7 @@ class Manager():
     app_name = "activitypub"
     version = "1.0.0"
     def __init__(self, context=None, defaults=None, database=None):
-        from .classes import ActivityPubBase
+        from ..classes import ActivityPubBase
         self.callback = lambda box, activity_id: None
         self.context = context
         self.defaults = defaults or self.make_defaults()
@@ -61,7 +63,7 @@ class Manager():
                                     self.version,
                                     self.expand_defaults("$SCHEME/$HOST"))
 
-    def expand_defaults(self, obj, string):
+    def expand_defaults(self, string, obj=None):
         """
         Expand a string with defaults.
         """
@@ -71,18 +73,19 @@ class Manager():
                     string = string.replace(key, self.defaults[key]())
                 else:
                     string = string.replace(key, self.defaults[key])
-        for key in self.parse(string):
-            if key.startswith("$"):
-                if getattr(obj, "ap_" + key[1:]) is None:
-                    raise Exception("expansion requires %s" % key[1:])
-                string = string.replace(key, getattr(obj, "ap_" + key[1:]))
+        if obj:
+            for key in self.parse(string):
+                if key.startswith("$"):
+                    if getattr(obj, "ap_" + key[1:]) is None:
+                        raise Exception("expansion requires %s" % key[1:])
+                    string = string.replace(key, getattr(obj, "ap_" + key[1:]))
         return string
 
     def parse(self, string):
         """
         Parse a string delimited by non-alpha, non-$ symbols.
 
-        >>> from activitypub import Manager
+        >>> from activitypub.manager import Manager
         >>> m = Manager()
         >>> m.parse("apple/banana/$variable")
         ['apple', 'banana', '$variable']
@@ -104,7 +107,7 @@ class Manager():
         return retval
 
     def from_dict(self, data):
-        from .classes import ActivityPubBase
+        from ..classes import ActivityPubBase
         return ActivityPubBase.from_dict(data)
 
     def to_list(self, item):
@@ -193,3 +196,45 @@ class Manager():
         response.raise_for_status()
         return response.json()
 
+    def get_secret_key(self, name):
+        filename = "%s.key" % name
+        if not os.path.exists():
+            key = binascii.hexlify(os.urandom(32)).decode("utf-8")
+            with open(filename, "w+") as f:
+                f.write(key)
+            return key
+        else:
+            with open(key_path) as f:
+                return f.read()
+
+    def get_rsa_key(self, owner, user, domain):
+        """"
+        Loads or generates an RSA key.
+        """
+        k = Key(owner)
+        user = user.replace(".", "_")
+        domain = domain.replace(".", "_")
+        key_path = os.path.join(KEY_DIR, f"key_{user}_{domain}.pem")
+        if os.path.isfile(key_path):
+            with open(key_path) as f:
+                privkey_pem = f.read()
+                k.load(privkey_pem)
+        else:
+            k.new()
+            with open(key_path, "w") as f:
+                f.write(k.privkey_pem)
+        return k
+
+    def after_request(self, f):
+        """
+        Decorator
+        """
+        return f
+
+    def template_filter(self):
+        """
+        Decorator
+        """
+        def decorator(f):
+            return f
+        return decorator
diff --git a/activitypub/manager/flaskman.py b/activitypub/manager/flaskman.py
new file mode 100644
index 0000000..c2cd6b0
--- /dev/null
+++ b/activitypub/manager/flaskman.py
@@ -0,0 +1,22 @@
+from flask import (Flask, Response)
+
+from .base import Manager
+    
+class FlaskManager(Manager):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.app = Flask(__name__)
+
+    def after_request(self, f):
+        """
+        Decorator
+        """
+        self.app.after_request(f)
+
+    def template_filter(self):
+        """
+        Decorator
+        """
+        def decorator(f):
+            self.app.template_filter()(f)
+        return decorator
diff --git a/activitypub/manager/tornadoman.py b/activitypub/manager/tornadoman.py
new file mode 100644
index 0000000..8413610
--- /dev/null
+++ b/activitypub/manager/tornadoman.py
@@ -0,0 +1,6 @@
+from .base import Manager
+
+class TornadoManager(Manager):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        #self.app = Flask(__name__)