diff -dupr a/httpbin/core.py b/httpbin/core.py
--- a/httpbin/core.py	2018-05-08 13:41:03.000000000 +0200
+++ b/httpbin/core.py	2019-11-22 15:07:27.516500217 +0100
@@ -21,7 +21,6 @@ from werkzeug.datastructures import WWWA
 from werkzeug.http import http_date
 from werkzeug.wrappers import BaseResponse
 from werkzeug.http import parse_authorization_header
-from raven.contrib.flask import Sentry
 
 from . import filters
 from .helpers import get_headers, status_code, get_dict, get_request_range, check_basic_auth, check_digest_auth, \
@@ -58,6 +57,7 @@ app.debug = bool(os.environ.get('DEBUG')
 
 # Send app errors to Sentry.
 if 'SENTRY_DSN' in os.environ:
+    from raven.contrib.flask import Sentry
     sentry = Sentry(app, dsn=os.environ['SENTRY_DSN'])
 
 # Set up Bugsnag exception tracking, if desired. To use Bugsnag, install the