diff --git a/plugins/nextcloud/nextcloud_ b/plugins/nextcloud/nextcloud_
index e7e57fcd..85538dfd 100755
--- a/plugins/nextcloud/nextcloud_
+++ b/plugins/nextcloud/nextcloud_
@@ -1,4 +1,5 @@
 #!/bin/sh
+# shellcheck shell=dash
 
 set -e
 
@@ -28,6 +29,10 @@ Set username and password in your munin-node configuration
 [nextcloud_cloud.domain.tld]
 env.username <nexcloud_user>
 env.password <nextcloud_password>
+env.api_path <default: /ocs/v2.php/apps/serverinfo/api/v1/info>
+env.scheme <default: https>
+env.timeout <default: 2s>
+env.updates_warning <default: 1>
 
 It's advised to set an app password (for this plugin) in your nextcloud 
 instance and not to use the "real" password of your nextcloud user.
@@ -47,44 +52,54 @@ GPLv2
 
 =cut
 
+# shellcheck disable=SC1090
 . "$MUNIN_LIBDIR/plugins/plugin.sh"
 
-API_PATH="/ocs/v2.php/apps/serverinfo/api/v1/info?format=json"
+if [ "${MUNIN_DEBUG:-0}" = 1 ]; then
+    set -x
+fi
+
+API_PATH="${api_path:-/ocs/v2.php/apps/serverinfo/api/v1/info}?format=json"
 DOMAIN="${0##*nextcloud_}"
+SCHEME="${scheme:-https}://"
+TIMEOUT="${timeout:-2}"
+UPDATES_WARNING="${updates_warning:-1}"
 CLEANDOMAIN="$(clean_fieldname "$DOMAIN")"
 USERNAME="${username:-}"
 PASSWORD="${password:-}"
 
 print_json_data() {
     local FIRST="$1"
-    [ -z "$FIRST" ] && exit 0
+    local VALUE="U"
     shift 1
+    test -z "$FIRST" && echo "missing data for 'print_json_data "" $*'">&2
     for KEY in "$@"; do
-        VALUE=$(echo "$FIRST" | jq -cr ".$KEY")
+        if [ -n "$FIRST" ]; then
+		VALUE=$(echo "$FIRST" | jq -cr ".$KEY")
+	fi
         echo "$KEY.value $VALUE"
    done
 }
 
-test_https() {
-    [ -z "$DOMAIN" ] && exit 0
-    curl -s -f -m 2 -I "https://$DOMAIN" > /dev/null && echo true && exit 0
+fetch_url () {
+    curl -s -f -m "${TIMEOUT}" "$@"
 }
 
 case $1 in
 
     autoconf)
-        if [ -x /usr/bin/curl ]; then
-            if [ -x /usr/bin/jq ]; then
-                [ "$(test_https)" ] && DOMAIN="https://$DOMAIN" || DOMAIN="http://$DOMAIN"
-                curl -s -f -m 2 -u "$USERNAME:$PASSWORD" -I "$DOMAIN$API_PATH" | grep -iq "Content-Type: application/json" && echo "yes" && exit 0 || echo "no (invalid or empty response from nextlcoud serverinfo api)" && exit 0
-            else
-                echo "no (jq not found)" && exit 0
-            fi
-        else
-            echo "no (/usr/bin/curl not found)" && exit 0
-        fi
-        ;;
-
+	    if [ ! -x "$(command -v curl)" ]; then
+		    echo "no (curl not found)"
+	    elif [ ! -x "$(command -v jq)" ]; then
+		    echo "no (jq not found)"exit 0
+	    else
+		    fetch_url -I -u "$USERNAME:$PASSWORD" -I "${SCHEME}${DOMAIN}${API_PATH}" \
+			    | grep -iq "Content-Type: application/json" \
+			    && echo "yes" \
+			    || echo "no (invalid or empty response from nextlcoud serverinfo api)"
+	    fi
+	    exit 0
+	    ;;
    config)
 
 cat << EOM
@@ -190,7 +205,7 @@ graph_category cloud
 num_updates_available.label available app updates
 num_updates_available.info number of available app updates
 num_updates_available.min 0
-num_updates_available.warning 1
+num_updates_available.warning ${UPDATES_WARNING}
 num_installed.label installed apps
 num_installed.info number of installed apps
 num_installed.min 0
@@ -201,8 +216,9 @@ EOM
 esac
 
 # Get JSON data
-[ "$(test_https)" ] && DOMAIN="https://$DOMAIN" || DOMAIN="http://$DOMAIN"
-JSONSTATS=$(curl -s -f -m 2 -u "$USERNAME:$PASSWORD" "$DOMAIN$API_PATH" | sed 's/\\/\\\\/g' | jq -cr ".ocs.data")
+JSONSTATS=$(
+	fetch_url -u "$USERNAME:$PASSWORD" "${SCHEME}${DOMAIN}${API_PATH}" | sed 's/\\/\\\\/g' | jq -cr ".ocs.data" 2>&1
+)
 USERS=$(echo "$JSONSTATS" | jq -cr ".activeUsers")
 STORAGE=$(echo "$JSONSTATS" | jq -cr ".nextcloud.storage")
 SHARES=$(echo "$JSONSTATS" | jq -cr ".nextcloud.shares")