diff --git a/fdroidserver/lint.py b/fdroidserver/lint.py
index ba6fd442..e8881a84 100644
--- a/fdroidserver/lint.py
+++ b/fdroidserver/lint.py
@@ -120,7 +120,11 @@ http_url_shorteners = [
 ]
 
 http_checks = https_enforcings + http_url_shorteners + [
-    (re.compile(r'.*github\.com/[^/]+/[^/]+\.git'),
+    (re.compile(r'^(?!https?://)[^/]+'),
+     _("URL must start with https:// or http://")),
+    (re.compile(r'^http://[^.]+\.(github|gitlab)\.io/'),
+     _("URL must start with https://")),
+    (re.compile(r'^https://(github|gitlab)\.com(/[^/]+){2,3}\.git'),
      _("Appending .git is not necessary")),
     (re.compile(r'^https://[^/]*(github|gitlab|bitbucket|rawgit)\.[a-zA-Z]+/([^/]+/){2,3}master/'),
      _("Use /HEAD instead of /master to point at a file in the default branch")),
diff --git a/tests/lint.TestCase b/tests/lint.TestCase
index 12285431..65f351c0 100755
--- a/tests/lint.TestCase
+++ b/tests/lint.TestCase
@@ -101,8 +101,12 @@ class LintTest(unittest.TestCase):
         self.assertFalse(anywarns)
 
         bad_urls = [
+            'github.com/my/proj',
+            'https://github.com/foo/bar.git',
+            'https://gitlab.com/group/subgroup/project.git',
             'https://raw.githubusercontent.com/Seva-coder/Finder/master/ChangeLog.txt',
             'https://github.com/scoutant/blokish/blob/master/README.md#changelog',
+            'http://htmlpreview.github.io/?https://github.com/my/project/blob/HEAD/index.html',
         ]
         anywarns = False
         logging.debug('bad urls:')