diff --git a/swh/web/ui/converters.py b/swh/web/ui/converters.py
--- a/swh/web/ui/converters.py
+++ b/swh/web/ui/converters.py
@@ -158,17 +158,29 @@
         Revision dictionary with the same keys as inputs, only:
         - sha1s are in hexadecimal strings (id, directory)
         - bytes are decoded in string (author_name, committer_name,
-        author_email, committer_email, message)
+        author_email, committer_email)
         - remaining keys are left as is
 
     """
-    return from_swh(revision,
-                    hashess=set(['id', 'directory', 'parents', 'children']),
-                    bytess=set(['name',
-                                'fullname',
-                                'email',
-                                'message']),
-                    dates={'date', 'committer_date'})
+    revision = from_swh(revision,
+                        hashess=set(['id',
+                                     'directory',
+                                     'parents',
+                                     'children']),
+                        bytess=set(['name',
+                                    'fullname',
+                                    'email']),
+                        dates={'date', 'committer_date'})
+
+    if revision:
+        if 'message' in revision:
+            try:
+                revision['message'] = revision['message'].decode('utf-8')
+            except UnicodeDecodeError:
+                revision['message_decoding_failed'] = True
+                revision['message'] = None
+
+    return revision
 
 
 def from_content(content):
diff --git a/swh/web/ui/service.py b/swh/web/ui/service.py
--- a/swh/web/ui/service.py
+++ b/swh/web/ui/service.py
@@ -215,9 +215,8 @@
         ['sha1'],
         'Only sha1_git is supported.')
 
-    res = backend.revision_get(sha1_git_bin)
-    res.pop('message', None)
-    return converters.from_revision(res)
+    revision = backend.revision_get(sha1_git_bin)
+    return converters.from_revision(revision)
 
 
 def lookup_revision_message(rev_sha1_git):
@@ -247,7 +246,7 @@
         raise NotFoundExc('No message for revision with sha1_git %s.'
                           % rev_sha1_git)
     res = {'message': revision['message']}
-    return converters.from_revision(res)
+    return res
 
 
 def lookup_revision_by(origin_id,
diff --git a/swh/web/ui/templates/revision-log.html b/swh/web/ui/templates/revision-log.html
--- a/swh/web/ui/templates/revision-log.html
+++ b/swh/web/ui/templates/revision-log.html
@@ -73,8 +73,18 @@
               <div class="col-md-2">Message</div>
               <div class="col-md-6"><pre>{{ revision['message'] }}</pre></div>
             </div>
-    {% endif %}
-
+    {% elif revision['message_encoding_failed'] %}
+	    <div class="row">
+              <div class="col-md-2">Message</div>
+              <div class="col-md-6"><a href="{{ revision['message_url'] }}">Download raw message</a></div>
+            </div
+    {% else %}
+            <div class="row">
+              <div class="col-md-2">Message</div>
+              <div class="col-md-6">No message found.</div>
+            </div>
+    {% endif %}	    
+	    
     {% for key in revision.keys() %}
            {% if key in ['type', 'synthetic'] and revision[key] is not none %}
             <div class="row">
diff --git a/swh/web/ui/templates/revision.html b/swh/web/ui/templates/revision.html
--- a/swh/web/ui/templates/revision.html
+++ b/swh/web/ui/templates/revision.html
@@ -56,6 +56,16 @@
               <div class="col-md-2">Message</div>
               <div class="col-md-6"><pre>{{ revision['message'] }}</pre></div>
             </div>
+    {% elif revision['message_encoding_failed'] %}
+	    <div class="row">
+              <div class="col-md-2">Message</div>
+              <div class="col-md-6"><a href="{{ revision['message_url'] }}">Download raw message</a></div>
+            </div
+    {% else %}
+            <div class="row">
+              <div class="col-md-2">Message</div>
+              <div class="col-md-6">No message found.</div>
+            </div>
     {% endif %}
 
     {% for key in revision.keys() %}
diff --git a/swh/web/ui/tests/test_converters.py b/swh/web/ui/tests/test_converters.py
--- a/swh/web/ui/tests/test_converters.py
+++ b/swh/web/ui/tests/test_converters.py
@@ -326,6 +326,107 @@
         self.assertEqual(actual_revision, expected_revision)
 
     @istest
+    def from_revision_invalid(self):
+        revision_input = {
+            'id': hashutil.hex_to_hash(
+                '18d8be353ed3480476f032475e7c233eff7371d5'),
+            'directory': hashutil.hex_to_hash(
+                '7834ef7e7c357ce2af928115c6c6a42b7e2a44e6'),
+            'author': {
+                'name': b'Software Heritage',
+                'fullname': b'robot robot@softwareheritage.org',
+                'email': b'robot@softwareheritage.org',
+            },
+            'committer': {
+                'name': b'Software Heritage',
+                'fullname': b'robot robot@softwareheritage.org',
+                'email': b'robot@softwareheritage.org',
+            },
+            'message': b'invalid message \xff',
+            'date': {
+                'timestamp': datetime.datetime(
+                    2000, 1, 17, 11, 23, 54,
+                    tzinfo=datetime.timezone.utc).timestamp(),
+                'offset': 0,
+                'negative_utc': False,
+            },
+            'committer_date': {
+                'timestamp': datetime.datetime(
+                    2000, 1, 17, 11, 23, 54,
+                    tzinfo=datetime.timezone.utc).timestamp(),
+                'offset': 0,
+                'negative_utc': False,
+            },
+            'synthetic': True,
+            'type': 'tar',
+            'parents': [
+                hashutil.hex_to_hash(
+                    '29d8be353ed3480476f032475e7c244eff7371d5'),
+                hashutil.hex_to_hash(
+                    '30d8be353ed3480476f032475e7c244eff7371d5')
+            ],
+            'children': [
+                hashutil.hex_to_hash(
+                    '123546353ed3480476f032475e7c244eff7371d5'),
+            ],
+            'metadata': {
+                'original_artifact': [{
+                    'archive_type': 'tar',
+                    'name': 'webbase-5.7.0.tar.gz',
+                    'sha1': '147f73f369733d088b7a6fa9c4e0273dcd3c7ccd',
+                    'sha1_git': '6a15ea8b881069adedf11feceec35588f2cfe8f1',
+                    'sha256': '401d0df797110bea805d358b85bcc1ced29549d3d73f'
+                    '309d36484e7edf7bb912',
+
+                }]
+            },
+        }
+
+        expected_revision = {
+            'id': '18d8be353ed3480476f032475e7c233eff7371d5',
+            'directory': '7834ef7e7c357ce2af928115c6c6a42b7e2a44e6',
+            'author': {
+                'name': 'Software Heritage',
+                'fullname': 'robot robot@softwareheritage.org',
+                'email': 'robot@softwareheritage.org',
+            },
+            'committer': {
+                'name': 'Software Heritage',
+                'fullname': 'robot robot@softwareheritage.org',
+                'email': 'robot@softwareheritage.org',
+            },
+            'message': None,
+            'message_decoding_failed': True,
+            'date': "2000-01-17T11:23:54+00:00",
+            'committer_date': "2000-01-17T11:23:54+00:00",
+            'children': [
+                '123546353ed3480476f032475e7c244eff7371d5'
+            ],
+            'parents': [
+                '29d8be353ed3480476f032475e7c244eff7371d5',
+                '30d8be353ed3480476f032475e7c244eff7371d5'
+            ],
+            'type': 'tar',
+            'synthetic': True,
+            'metadata': {
+                'original_artifact': [{
+                    'archive_type': 'tar',
+                    'name': 'webbase-5.7.0.tar.gz',
+                    'sha1': '147f73f369733d088b7a6fa9c4e0273dcd3c7ccd',
+                    'sha1_git': '6a15ea8b881069adedf11feceec35588f2cfe8f1',
+                    'sha256': '401d0df797110bea805d358b85bcc1ced29549d3d73f'
+                    '309d36484e7edf7bb912'
+                }]
+            },
+        }
+
+        # when
+        actual_revision = converters.from_revision(revision_input)
+
+        # then
+        self.assertEqual(actual_revision, expected_revision)
+
+    @istest
     def from_content(self):
         content_input = {
             'sha1': hashutil.hex_to_hash('5c6f0e2750f48fa0bd0c4cf5976ba0b9e0'
diff --git a/swh/web/ui/tests/test_service.py b/swh/web/ui/tests/test_service.py
--- a/swh/web/ui/tests/test_service.py
+++ b/swh/web/ui/tests/test_service.py
@@ -929,6 +929,76 @@
                 'name': 'boule & bill',
                 'email': 'boule@bill.org',
             },
+            'message': 'elegant fix for bug 31415957',
+            'date': "2000-01-17T11:23:54+00:00",
+            'committer_date': "2000-01-17T11:23:54+00:00",
+            'synthetic': False,
+            'type': 'git',
+            'parents': [],
+            'metadata': [],
+        })
+
+        mock_backend.revision_get.assert_called_with(
+            hex_to_hash('18d8be353ed3480476f032475e7c233eff7371d5'))
+
+    @patch('swh.web.ui.service.backend')
+    @istest
+    def lookup_revision_invalid_msg(self, mock_backend):
+        # given
+        stub_rev = {
+            'id': hex_to_hash('123456'),
+            'directory': hex_to_hash(
+                '7834ef7e7c357ce2af928115c6c6a42b7e2a44e6'),
+            'author': {
+                'name': b'bill & boule',
+                'email': b'bill@boule.org',
+            },
+            'committer': {
+                'name': b'boule & bill',
+                'email': b'boule@bill.org',
+            },
+            'message': b'elegant fix for bug \xff',
+            'date': {
+                'timestamp': datetime.datetime(
+                    2000, 1, 17, 11, 23, 54,
+                    tzinfo=datetime.timezone.utc,
+                ).timestamp(),
+                'offset': 0,
+                'negative_utc': False,
+            },
+            'committer_date': {
+                'timestamp': datetime.datetime(
+                    2000, 1, 17, 11, 23, 54,
+                    tzinfo=datetime.timezone.utc,
+                ).timestamp(),
+                'offset': 0,
+                'negative_utc': False,
+            },
+            'synthetic': False,
+            'type': 'git',
+            'parents': [],
+            'metadata': [],
+        }
+        mock_backend.revision_get = MagicMock(return_value=stub_rev)
+
+        # when
+        actual_revision = service.lookup_revision(
+            '18d8be353ed3480476f032475e7c233eff7371d5')
+
+        # then
+        self.assertEqual(actual_revision, {
+            'id': '123456',
+            'directory': '7834ef7e7c357ce2af928115c6c6a42b7e2a44e6',
+            'author': {
+                'name': 'bill & boule',
+                'email': 'bill@boule.org',
+            },
+            'committer': {
+                'name': 'boule & bill',
+                'email': 'boule@bill.org',
+            },
+            'message': None,
+            'message_decoding_failed': True,
             'date': "2000-01-17T11:23:54+00:00",
             'committer_date': "2000-01-17T11:23:54+00:00",
             'synthetic': False,
@@ -984,7 +1054,7 @@
             '18d8be353ed3480476f032475e7c233eff7371d5')
 
         # then
-        self.assertEquals(rv, {'message': 'elegant fix for bug 31415957'})
+        self.assertEquals(rv, {'message': b'elegant fix for bug 31415957'})
         mock_backend.revision_get.assert_called_with(
             hex_to_hash('18d8be353ed3480476f032475e7c233eff7371d5'))
 
diff --git a/swh/web/ui/tests/test_utils.py b/swh/web/ui/tests/test_utils.py
--- a/swh/web/ui/tests/test_utils.py
+++ b/swh/web/ui/tests/test_utils.py
@@ -570,3 +570,104 @@
              call('api_revision_history',
                   sha1_git_root='sha1_git_root',
                   sha1_git='456')])
+
+    @patch('swh.web.ui.utils.flask')
+    @istest
+    def enrich_revision_with_no_message(self, mock_flask):
+        # given
+        def url_for_test(fn, **data):
+            print(fn, data)
+            if fn == 'api_revision':
+                return '/api/revision/' + data['sha1_git'] + '/'
+            elif fn == 'api_revision_log':
+                return '/api/revision/' + data['sha1_git'] + '/log/'
+            elif fn == 'api_revision_raw_message':
+                return '/api/revision/' + data['sha1_git'] + '/raw/'
+            else:
+                return '/api/revision/' + data['sha1_git_root'] + '/history/' + data['sha1_git'] + '/'  # noqa
+
+        mock_flask.url_for.side_effect = url_for_test
+
+        # when
+        actual_revision = utils.enrich_revision({
+            'id': 'rev-id',
+            'message': None,
+            'parents': ['123'],
+            'children': ['456'],
+        }, context='sha1_git_root')
+
+        # then
+        self.assertEqual(actual_revision, {
+            'id': 'rev-id',
+            'url': '/api/revision/rev-id/',
+            'message': None,
+            'history_url': '/api/revision/rev-id/log/',
+            'parents': ['123'],
+            'parent_urls': ['/api/revision/sha1_git_root/history/123/'],
+            'children': ['456'],
+            'children_urls': ['/api/revision/sha1_git_root/history/456/'],
+        })
+
+        mock_flask.url_for.assert_has_calls(
+            [call('api_revision',
+                  sha1_git='rev-id'),
+             call('api_revision_log',
+                  sha1_git='rev-id'),
+             call('api_revision_history',
+                  sha1_git_root='sha1_git_root',
+                  sha1_git='123'),
+             call('api_revision_history',
+                  sha1_git_root='sha1_git_root',
+                  sha1_git='456')])
+
+    @patch('swh.web.ui.utils.flask')
+    @istest
+    def enrich_revision_with_invalid_message(self, mock_flask):
+        # given
+        def url_for_test(fn, **data):
+            print(fn, data)
+            if fn == 'api_revision':
+                return '/api/revision/' + data['sha1_git'] + '/'
+            elif fn == 'api_revision_log':
+                return '/api/revision/' + data['sha1_git'] + '/log/'
+            elif fn == 'api_revision_raw_message':
+                return '/api/revision/' + data['sha1_git'] + '/raw/'
+            else:
+                return '/api/revision/' + data['sha1_git_root'] + '/history/' + data['sha1_git'] + '/'  # noqa
+
+        mock_flask.url_for.side_effect = url_for_test
+
+        # when
+        actual_revision = utils.enrich_revision({
+            'id': 'rev-id',
+            'message': None,
+            'message_decoding_failed': True,
+            'parents': ['123'],
+            'children': ['456'],
+        }, context='sha1_git_root')
+
+        # then
+        self.assertEqual(actual_revision, {
+            'id': 'rev-id',
+            'url': '/api/revision/rev-id/',
+            'message': None,
+            'message_decoding_failed': True,
+            'message_url': '/api/revision/rev-id/raw/',
+            'history_url': '/api/revision/rev-id/log/',
+            'parents': ['123'],
+            'parent_urls': ['/api/revision/sha1_git_root/history/123/'],
+            'children': ['456'],
+            'children_urls': ['/api/revision/sha1_git_root/history/456/'],
+        })
+
+        mock_flask.url_for.assert_has_calls(
+            [call('api_revision',
+                  sha1_git='rev-id'),
+             call('api_revision_log',
+                  sha1_git='rev-id'),
+             call('api_revision_history',
+                  sha1_git_root='sha1_git_root',
+                  sha1_git='123'),
+             call('api_revision_history',
+                  sha1_git_root='sha1_git_root',
+                  sha1_git='456')])
diff --git a/swh/web/ui/tests/views/test_api.py b/swh/web/ui/tests/views/test_api.py
--- a/swh/web/ui/tests/views/test_api.py
+++ b/swh/web/ui/tests/views/test_api.py
@@ -723,16 +723,12 @@
         mock_service.lookup_revision_message.return_value = stub_revision
 
         # when
-        rv = self.app.get('/api/1/revision/'
-                          '18d8be353ed3480476f032475e7c233eff7371d5/raw/')
-
+        rv = self.app.get('/api/1/revision/18d8be353ed3480476f032475e7c2'
+                          '33eff7371d5/raw/')
         # then
         self.assertEquals(rv.status_code, 200)
-        self.assertEquals(rv.mimetype, 'application/json')
-
-        response_data = json.loads(rv.data.decode('utf-8'))
-        self.assertEquals(response_data,
-                          {'message': 'synthetic revision message'})
+        self.assertEquals(rv.mimetype, 'application/octet-stream')
+        self.assertEquals(rv.data, b'synthetic revision message')
 
         mock_service.lookup_revision_message.assert_called_once_with(
             '18d8be353ed3480476f032475e7c233eff7371d5')
diff --git a/swh/web/ui/tests/views/test_browse.py b/swh/web/ui/tests/views/test_browse.py
--- a/swh/web/ui/tests/views/test_browse.py
+++ b/swh/web/ui/tests/views/test_browse.py
@@ -839,6 +839,19 @@
 
     @patch('swh.web.ui.views.browse.api')
     @istest
+    def browse_revision_raw_message(self, mock_api):
+        # given
+        sha1 = 'd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754'
+
+        # when
+        rv = self.client.get('/browse/revision/'
+                             'd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754/raw/')
+
+        self.assertRedirects(
+            rv, '/api/1/revision/%s/raw/' % sha1)
+
+    @patch('swh.web.ui.views.browse.api')
+    @istest
     def browse_revision_log_ko_not_found(self, mock_api):
         # given
         mock_api.api_revision_log.side_effect = NotFoundExc('Not found!')
diff --git a/swh/web/ui/utils.py b/swh/web/ui/utils.py
--- a/swh/web/ui/utils.py
+++ b/swh/web/ui/utils.py
@@ -242,4 +242,11 @@
 
         revision['children_urls'] = children
 
+    if 'message' in revision:
+        if 'message_decoding_failed' in revision:
+            if revision['message_decoding_failed']:
+                revision['message_url'] = flask.url_for(
+                    'api_revision_raw_message',
+                    sha1_git=revision['id'])
+
     return revision
diff --git a/swh/web/ui/views/api.py b/swh/web/ui/views/api.py
--- a/swh/web/ui/views/api.py
+++ b/swh/web/ui/views/api.py
@@ -512,8 +512,11 @@
         GET /api/1/revision/baf18f9fc50a0b6fef50460a76c33b2ddc57486e/raw/
 
     """
-
-    return service.lookup_revision_message(sha1_git)
+    raw = service.lookup_revision_message(sha1_git)
+    return Response(raw['message'],
+                    headers={'Content-disposition': 'attachment;'
+                             'filename=rev_%s_raw' % sha1_git},
+                    mimetype='application/octet-stream')
 
 
 @app.route('/api/1/revision/<string:sha1_git>/directory/')
diff --git a/swh/web/ui/views/browse.py b/swh/web/ui/views/browse.py
--- a/swh/web/ui/views/browse.py
+++ b/swh/web/ui/views/browse.py
@@ -332,6 +332,14 @@
     return render_template('revision.html', **env)
 
 
+@app.route('/browse/revision/<string:sha1_git>/raw/')
+def browse_revision_raw_message(sha1_git):
+    """Given a sha1_git, display the corresponding revision's raw message.
+
+    """
+    return redirect(url_for('api_revision_raw_message', sha1_git=sha1_git))
+
+
 @app.route('/browse/revision/<string:sha1_git>/log/')
 @set_renderers(HTMLRenderer)
 def browse_revision_log(sha1_git):