diff --git a/fabfile.py b/fabfile.py
index 175ac519d..c1a61d48a 100644
--- a/fabfile.py
+++ b/fabfile.py
@@ -1,12 +1,28 @@
 from fabric.api import local, run, lcd, cd, env
 from os.path import exists as file_exists
-from fabtools.python import virtualenv
+from fabtools.python import install, is_installed, virtualenv, install_requirements
 from os import path
 import json
 
 
 PWD = path.dirname(__file__)
 VENV_DIR = path.join(PWD, '.env')
+DEV_ENV_DIR = path.join(PWD, '.denv')
+
+
+def require_dep(name):
+    local('pip install %s' % name)
+
+def dev():
+    # Allow this to persist, since we aren't as rigorous about keeping state clean
+    if not file_exists('.denv'):
+        local('virtualenv .denv')
+ 
+    with virtualenv(DEV_ENV_DIR):
+        require_dep('cython')
+        require_dep('murmurhash')
+        require_dep('numpy')
+        local('pip install -r requirements.txt')
 
 
 def sdist():
diff --git a/setup.py b/setup.py
index ac7a213ee..c40d0f118 100644
--- a/setup.py
+++ b/setup.py
@@ -83,7 +83,7 @@ setup(
     description="Industrial-strength NLP",
     author='Matthew Honnibal',
     author_email='honnibal@gmail.com',
-    version='0.12',
+    version='0.13',
     url="http://honnibal.github.io/spaCy/",
     package_data={"spacy": ["*.pxd"],
                   "spacy.en": ["*.pxd", "data/pos/*",
@@ -93,5 +93,6 @@ setup(
     ext_modules=exts,
     license="Dual: Commercial or AGPL",
     install_requires=['murmurhash', 'cymem', 'preshed', 'thinc', "unidecode",
-                      "ujson"]
+                      "ujson"],
+    setup_requires=["murmurhash", "numpy"],
 )