diff --git a/README.md b/README.md
index 04d5170e..130eb00c 100644
--- a/README.md
+++ b/README.md
@@ -22,8 +22,8 @@ On Arch/Parabola:
 sudo pacman -S tor python-pip python-pysocks python-pycryptodome \
                imagemagick python-pillow python-requests \
 	       perl-image-exiftool python-numpy python-dateutil \
-	       python-qrcode python-png certbot flake8
-suso pip3 install pyLD
+	       certbot flake8
+sudo pip3 install pyLD pyqrcode pypng
 ```
 
 Or on Debian:
diff --git a/deploy/i2p b/deploy/i2p
index 23ec38c3..47a2ea8b 100755
--- a/deploy/i2p
+++ b/deploy/i2p
@@ -57,8 +57,8 @@ if [ -f /usr/bin/pacman ]; then
     pacman -S --noconfirm python-pip python-pysocks python-pycryptodome \
            imagemagick python-pillow python-requests \
 	   perl-image-exiftool python-numpy python-dateutil \
-	   python-qrcode certbot flake8 git i2pd wget qrencode
-    pip3 install pyLD
+	   certbot flake8 git i2pd wget qrencode
+    pip3 install pyLD pyqrcode pypng
 else
     apt-get update
     apt-get -y install imagemagick python3-crypto python3-pycryptodome \
diff --git a/deploy/onion b/deploy/onion
index b2d076c5..6c1093c0 100755
--- a/deploy/onion
+++ b/deploy/onion
@@ -38,8 +38,8 @@ if [ -f /usr/bin/pacman ]; then
     pacman -S --noconfirm tor python-pip python-pysocks python-pycryptodome \
            imagemagick python-pillow python-requests \
 	   perl-image-exiftool python-numpy python-dateutil \
-	   python-qrcode certbot flake8 git qrencode
-    pip3 install pyLD
+	   certbot flake8 git qrencode
+    pip3 install pyLD pyqrcode pypng
 else
     apt-get update
     apt-get -y install imagemagick python3-crypto python3-pycryptodome \
diff --git a/tests.py b/tests.py
index d062c337..906f6f42 100644
--- a/tests.py
+++ b/tests.py
@@ -31,6 +31,7 @@ from follow import clearFollows
 from follow import clearFollowers
 from follow import sendFollowRequestViaServer
 from follow import sendUnfollowRequestViaServer
+from utils import siteIsActive
 from utils import updateRecentPostsCache
 from utils import followPerson
 from utils import getNicknameFromActor
@@ -1858,8 +1859,15 @@ def testJsonld():
     assert(jsonldVerify(signedDocument, publicKeyPem))
 
 
+def testSiteIsActive():
+    print('testSiteIsActive')
+    assert(siteIsActive('https://mastodon.social'))
+    assert(not siteIsActive('https://notarealwebsite.a.b.c'))
+
+
 def runAllTests():
     print('Running tests...')
+    testSiteIsActive()
     testJsonld()
     testRemoveTextFormatting()
     testWebLinks()
diff --git a/utils.py b/utils.py
index b310735e..881f75e4 100644
--- a/utils.py
+++ b/utils.py
@@ -11,6 +11,8 @@ import time
 import shutil
 import datetime
 import json
+from urllib.request import urlopen
+from urllib.request import URLError
 from pprint import pprint
 from calendar import monthrange
 
@@ -1066,3 +1068,15 @@ def updateAnnounceCollection(recentPostsCache: {},
             print('DEBUG: saving post with shares (announcements) added')
             pprint(postJsonObject)
         saveJson(postJsonObject, postFilename)
+
+
+def siteIsActive(url: str) -> bool:
+    """Returns true if the current url is resolvable.
+    This can be used to check that an instance is online before
+    trying to send posts to it.
+    """
+    try:
+        urlopen(url, timeout=10)
+        return True
+    except URLError as err:
+        return False