diff --git a/swh/web/common/swh_templatetags.py b/swh/web/common/swh_templatetags.py
index dcac3b30..eab6cbef 100644
--- a/swh/web/common/swh_templatetags.py
+++ b/swh/web/common/swh_templatetags.py
@@ -1,182 +1,185 @@
 # Copyright (C) 2017-2019  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU Affero General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import json
 import re
 
 from django import template
 from django.core.serializers.json import DjangoJSONEncoder
 from django.utils.safestring import mark_safe
 
 from docutils.core import publish_parts
 from docutils.writers.html4css1 import Writer, HTMLTranslator
 from inspect import cleandoc
 
 from swh.web.common.origin_save import get_savable_origin_types
 
 register = template.Library()
 
 
 class NoHeaderHTMLTranslator(HTMLTranslator):
     """
     Docutils translator subclass to customize the generation of HTML
     from reST-formatted docstrings
     """
     def __init__(self, document):
         super().__init__(document)
         self.body_prefix = []
         self.body_suffix = []
 
     def visit_bullet_list(self, node):
         self.context.append((self.compact_simple, self.compact_p))
         self.compact_p = None
         self.compact_simple = self.is_compactable(node)
         self.body.append(self.starttag(node, 'ul', CLASS='docstring'))
 
 
 DOCSTRING_WRITER = Writer()
 DOCSTRING_WRITER.translator_class = NoHeaderHTMLTranslator
 
 
 @register.filter
 def safe_docstring_display(docstring):
     """
     Utility function to htmlize reST-formatted documentation in browsable
     api.
     """
     docstring = cleandoc(docstring)
     return publish_parts(docstring, writer=DOCSTRING_WRITER)['html_body']
 
 
 @register.filter
 def urlize_links_and_mails(text):
     """Utility function for decorating api links in browsable api.
 
     Args:
         text: whose content matching links should be transformed into
         contextual API or Browse html links.
 
     Returns
         The text transformed if any link is found.
         The text as is otherwise.
 
     """
-    if 'href="' not in text:
-        text = re.sub(r'(/api/[^"<]*|/browse/[^"<]*|http.*$)',
-                      r'<a href="\1">\1</a>',
-                      text)
-        return re.sub(r'([^ <>"]+@[^ <>"]+)',
-                      r'<a href="mailto:\1">\1</a>',
-                      text)
-    else:
-        return text
+    try:
+        if 'href="' not in text:
+            text = re.sub(r'(/api/[^"<]*|/browse/[^"<]*|http.*$)',
+                          r'<a href="\1">\1</a>',
+                          text)
+            return re.sub(r'([^ <>"]+@[^ <>"]+)',
+                          r'<a href="mailto:\1">\1</a>',
+                          text)
+    except Exception:
+        pass
+
+    return text
 
 
 @register.filter
 def urlize_header_links(text):
     """Utility function for decorating headers links in browsable api.
 
     Args
         text: Text whose content contains Link header value
 
     Returns:
         The text transformed with html link if any link is found.
         The text as is otherwise.
 
     """
     links = text.split(',')
     ret = ''
     for i, link in enumerate(links):
         ret += re.sub(r'<(/api/.*|/browse/.*)>', r'<<a href="\1">\1</a>>',
                       link)
         # add one link per line and align them
         if i != len(links) - 1:
             ret += '\n     '
     return ret
 
 
 @register.filter
 def jsonify(obj):
     """Utility function for converting a django template variable
     to JSON in order to use it in script tags.
 
     Args
         obj: Any django template context variable
 
     Returns:
         JSON representation of the variable.
 
     """
     return mark_safe(json.dumps(obj, cls=DjangoJSONEncoder))
 
 
 @register.filter
 def sub(value, arg):
     """Django template filter for subtracting two numbers
 
     Args:
         value (int/float): the value to subtract from
         arg (int/float): the value to subtract to
 
     Returns:
         int/float: The subtraction result
     """
     return value - arg
 
 
 @register.filter
 def mul(value, arg):
     """Django template filter for multiplying two numbers
 
     Args:
         value (int/float): the value to multiply from
         arg (int/float): the value to multiply with
 
     Returns:
         int/float: The multiplication result
     """
     return value * arg
 
 
 @register.filter
 def key_value(dict, key):
     """Django template filter to get a value in a dictionary.
 
         Args:
             dict (dict): a dictionary
             key (str): the key to lookup value
 
         Returns:
             The requested value in the dictionary
     """
     return dict[key]
 
 
 @register.filter
 def origin_type_savable(origin_type):
     """Django template filter to check if a save request can be
     created for a given origin type.
 
         Args:
             origin_type (str): the type of software origin
 
         Returns:
             If the origin type is savable or not
     """
     return origin_type in get_savable_origin_types()
 
 
 @register.filter
 def split(value, arg):
     """Django template filter to split a string.
 
         Args:
             value (str): the string to split
             arg (str): the split separator
 
         Returns:
             list: the splitted string parts
     """
     return value.split(arg)
diff --git a/swh/web/templates/api/apidoc.html b/swh/web/templates/api/apidoc.html
index 903d8f5f..f377cb00 100644
--- a/swh/web/templates/api/apidoc.html
+++ b/swh/web/templates/api/apidoc.html
@@ -1,183 +1,183 @@
 {% extends "layout.html" %}
 
 {% comment %}
 Copyright (C) 2015-2019  The Software Heritage developers
 See the AUTHORS file at the top-level directory of this distribution
 License: GNU Affero General Public License version 3, or any later version
 See top-level LICENSE file for more information
 {% endcomment %}
 
 {% load swh_templatetags %}
 
 {% block title %}{{ heading }} &ndash; Software Heritage API {% endblock %}
 
 {% block navbar-content %}
 <nav class="bread-crumbs">
   <ul>
     <li><a href="/api/"><h4>Web API</h4></a></li>
     <li class="bc-no-root"><i class="fa fa-caret-right fa-fw" aria-hidden="true"></i></li>
     <li class="bc-no-root"><a href="/api/1/">endpoints</a></li>
     {% for endpoint in endpoint_path %}
       <li class="bc-no-root"><i class="fa fa-caret-right fa-fw" aria-hidden="true"></i></li>
       {% if endpoint.name != 'stat' and endpoint.name != 'vault' and endpoint.path != 'vault/revision' %}
         <li class="bc-no-root"><a href="{{ '/api/1/'|add:endpoint.path }}">{{ endpoint.name }}</a></li>
       {% else %}
         <li class="bc-no-root"><span>{{ endpoint.name }}</span></li>
       {% endif %}
     {% endfor %}
   </ul>
 </nav>
 {% endblock %}
 
 {% block content %}
 
 <div class='swh-apidoc'>
 {% if description %}
   <div>
     <h4> Description </h4>
     {{ description | safe_docstring_display | safe }}
   </div>
 {% endif %}
-{% if response_data  %}
+{% if response_data is not None %}
   <div>
     <h4>Request</h4>
     <pre><strong>{{ request.method }}</strong> {{ request.path }}</pre>
     <hr/>
     <h4>Response</h4>
     {% if status_code != 200 %}
       <h5>Status Code</h5>
       <pre>{{ status_code }}</pre>
     {% endif %}
     {% if headers_data %}
       <h5>Headers</h5>
       {% for header_name, header_value in headers_data.items %}
         <pre><strong>{{ header_name }}</strong> {{ header_value | urlize_header_links | safe }}</pre>
       {% endfor %}
     {% endif %}
     <h5>Body</h5>
     <pre><code class="json">{{ response_data | urlize_links_and_mails | safe }}</code></pre>
   </div>
 {% endif %}
 <hr/>
 {% if urls and urls|length > 0 %}
   <div>
     <table class="m-x-auto table">
       <thead>
         <tr>
           <th>URL</th>
           <th>Allowed Methods</th>
         </tr>
       </thead>
       <tbody>
         {% for url in urls %}
           <tr>
             <td>{{ url.rule | safe_docstring_display | safe }}</td>
             <td>{{ url.methods | dictsort:0 | join:', ' }}</td>
           </tr>
         {% endfor %}
       </tbody>
     </table>
   </div>
   <hr/>
 {% endif %}
 {% if args and args|length > 0 %}
   <div>
     <h4> Arguments </h4>
     {% for arg in args %}
       <dl class="row">
         <dt class="col col-md-2 text-right"> {{ arg.name }} ({{ arg.type }}) </dt>
         <dd class="col col-md-9"> {{ arg.doc | safe_docstring_display | safe }} </dd>
       </dl>
     {% endfor %}
   </div>
   <hr/>
 {% endif %}
 {% if params and params|length > 0 %}
   <div>
     <h4> Query parameters </h4>
     {% for param in params %}
       <dl class="row">
         <dt class="col col-md-2 text-right"> {{ param.name }} ({{ param.type }}) </dt>
         <dd class="col col-md-9"> {{ param.doc | safe_docstring_display | safe }} </dd>
       </dl>
     {% endfor %}
   </div>
   <hr/>
 {% endif %}
 {% if reqheaders and reqheaders|length > 0 %}
   <div>
     <h4> Request headers </h4>
     {% for header in reqheaders %}
       <dl class="row">
         <dt class="col col-md-2 text-right"> {{ header.name }} </dt>
         <dd class="col col-md-9"> {{ header.doc | safe_docstring_display | safe }} </dd>
       </dl>
     {% endfor %}
   </div>
 <hr/>
 {% endif %}
 {% if resheaders and resheaders|length > 0 %}
   <div>
     <h4> Response headers </h4>
     {% for header in resheaders %}
       <dl class="row">
         <dt class="col col-md-2 text-right"> {{ header.name }} </dt>
         <dd class="col col-md-9"> {{ header.doc | safe_docstring_display | safe }} </dd>
       </dl>
     {% endfor %}
   </div>
 <hr/>
 {% endif %}
 {% if return_type %}
   <div>
     <h4> Returns </h4>
     <dl class="row">
       <dt class="col col-md-2 text-right"> {{ return_type }} </dt>
       <dd class="col col-md-9">
         <p>
           {% if return_type == 'array' %}
             an array of objects containing the following keys:
           {% elif return_type == 'octet stream' %}
             the raw data as an octet stream
           {% else %}
             an object containing the following keys:
           {% endif %}
           {{ returns_list | safe_docstring_display | safe }}
         </p>
       </dd>
     </dl>
   </div>
   <hr/>
 {% endif %}
 {% if status_codes and status_codes|length > 0 %}
   <div>
     <h4> HTTP status codes </h4>
     {% for status in status_codes %}
       <dl class="row">
         <dt class="col col-md-2 text-right"> {{ status.code }} </dt>
         <dd class="col col-md-9"> {{ status.doc | safe_docstring_display | safe }} </dd>
       </dl>
     {% endfor %}
   </div>
   <hr/>
 {% endif %}
 {% if examples and examples|length > 0 %}
   <div>
     <h4> Examples </h4>
     {% for example in examples %}
       <dl class="row">
         <dt class="col col-md-2"></dt>
         <dd class="col col-md-9">
           <a href="{{ example }}">{{ example }}</a>
         </dd>
       </dl>
     {% endfor %}
   </div>
 {% endif %}
 </div>
 
 <script>
   swh.webapp.initPage('api');
   swh.webapp.highlightCode(false);
 </script>
 {% endblock %}