diff --git a/helpers0.py b/helpers0.py
new file mode 100644
index 0000000..f163498
--- /dev/null
+++ b/helpers0.py
@@ -0,0 +1,61 @@
+import requests
+import urllib.parse
+
+from flask import redirect, render_template, request, session
+from functools import wraps
+
+
+def apology(message, code=400):
+    """Render message as an apology to user."""
+    def escape(s):
+        """
+        Escape special characters.
+
+        https://github.com/jacebrowning/memegen#special-characters
+        """
+        for old, new in [("-", "--"), (" ", "-"), ("_", "__"), ("?", "~q"),
+                         ("%", "~p"), ("#", "~h"), ("/", "~s"), ("\"", "''")]:
+            s = s.replace(old, new)
+        return s
+    return render_template("apology.html", top=code, bottom=escape(message)), code
+
+
+def login_required(f):
+    """
+    Decorate routes to require login.
+
+    http://flask.pocoo.org/docs/1.0/patterns/viewdecorators/
+    """
+    @wraps(f)
+    def decorated_function(*args, **kwargs):
+        if session.get("user_id") is None:
+            return redirect("/login")
+        return f(*args, **kwargs)
+    return decorated_function
+
+
+def lookup(symbol):
+    """Look up quote for symbol."""
+
+    # Contact API
+    try:
+        response = requests.get(f"https://api.iextrading.com/1.0/stock/{urllib.parse.quote_plus(symbol)}/quote")
+        response.raise_for_status()
+    except requests.RequestException:
+        return None
+
+    # Parse response
+    try:
+        quote = response.json()
+        return {
+            "name": quote["companyName"],
+            "price": float(quote["latestPrice"]),
+            "symbol": quote["symbol"]
+        }
+    except (KeyError, TypeError, ValueError):
+        return None
+
+
+def usd(value):
+    """Format value as USD."""
+    return f"${value:,.2f}"
diff --git a/requirements.txt b/requirements.txt
index 191f5e5..8917ccb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -28,6 +28,7 @@ Flask-WTF==0.14.2
 gast==0.2.2
 google-pasta==0.1.7
 grpcio==1.24.1
+gunicorn==20.0.4
 h5py==2.10.0
 idna==2.8
 importlib-metadata==0.23