diff --git a/api/gitlab-bash-api.sh b/api/gitlab-bash-api.sh
index 4ba54de..71925c0 100644
--- a/api/gitlab-bash-api.sh
+++ b/api/gitlab-bash-api.sh
@@ -25,9 +25,8 @@ function gitlab_get_page {
   local page="$3"
 
   local curl_url="${GITLAB_URL_PREFIX}/api/${GITLAB_API_VERSION}/${api_url}?page=${page}&per_page=${PER_PAGE_MAX}&${api_params}"
-  local curl_result
-
-  curl_result="$( curl --include --silent --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" "${curl_url}" )"
+  local curl_result=
+  curl_result="$( curl --include --silent --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" "${curl_url}" ${client_certificate} )"
   local curl_rc=$?
 
   if [ ${curl_rc} -ne 0 ]; then
@@ -106,9 +105,8 @@ function gitlab_post {
   local api_params="$2"
 
   local curl_url="${GITLAB_URL_PREFIX}/api/${GITLAB_API_VERSION}/${api_url}?per_page=${PER_PAGE_MAX}&${api_params}"
-  local curl_result
-
-  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X POST --silent "${curl_url}" )"
+  local curl_result=
+  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X POST --silent "${curl_url}" ${client_certificate} )"
   local curl_rc=$?
 
   if [ ${curl_rc} -ne 0 ]; then
@@ -127,9 +125,8 @@ function gitlab_put {
   local api_params="$2"
 
   local curl_url="${GITLAB_URL_PREFIX}/api/${GITLAB_API_VERSION}/${api_url}?per_page=${PER_PAGE_MAX}&${api_params}"
-  local curl_result
-
-  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X PUT --silent "${curl_url}" )"
+  local curl_result=
+  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X PUT --silent "${curl_url}" ${client_certificate} )"
   local curl_rc=$?
 
   if [ ${curl_rc} -ne 0 ]; then
@@ -148,9 +145,8 @@ function gitlab_delete {
   local api_params="$2"
 
   local curl_url="${GITLAB_URL_PREFIX}/api/${GITLAB_API_VERSION}/${api_url}?per_page=${PER_PAGE_MAX}&${api_params}"
-  local curl_result
-
-  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X DELETE --silent "${curl_url}" )"
+  local curl_result=
+  curl_result="$( curl --header "PRIVATE-TOKEN: ${GITLAB_PRIVATE_TOKEN}" -X DELETE --silent "${curl_url}" ${client_certificate} )"
   local curl_rc=$?
 
   if [ ${curl_rc} -ne 0 ]; then
@@ -174,26 +170,26 @@ function url_encode {
 }
 
 function source_all_files_in_directory {
-  local folder=$1
-  local file
+  local -r folder=$1
 
+  local file=
   for file in "${folder}"/* ; do
     source "${file}"
   done
 }
 
 function list_projects_in_group {
-  local group_name=$1
-  local answer
+  local -r group_name="$1"
 
+  local answer=
   answer="$( list_projects_raw )"
 
   # Rewrite result
-  local result_for_group
-  local size
-
+  local curl_result=
   curl_result="$( echo "${answer}" | jq "[.[] | select(.namespace.name==\"${group_name}\")]" )" || exit $?
-  size="$( echo "${result_for_group}" |jq '. | length' )"
+
+  local size=
+  size="$( echo "${result_for_group}" | jq '. | length' )"
 
   if [ "${size}" -eq 0 ] ; then
     echo "No project available for group [${group_name}] (group does not exist ?)" >&2
@@ -396,3 +392,16 @@ if [ -z "${PER_PAGE_MAX}" ]; then
   # Max value for GitLab is 100
   PER_PAGE_MAX=50
 fi
+
+#
+# Prepare client_certificate part of CURL
+#
+if [ -n "${GITLAB_CLIENT_CERTIFICATE:-}" ]; then
+  client_certificate=" --cert ${GITLAB_CLIENT_CERTIFICATE}"
+  if [ -n "${GITLAB_CLIENT_CERTIFICATE_PASSWORD}" ]; then
+    client_certificate+=":${GITLAB_CLIENT_CERTIFICATE_PASSWORD}"
+  fi
+  client_certificate+=" --key ${GITLAB_PRIVATE_KEY}"
+else
+  client_certificate=
+fi
diff --git a/custom-config-sample/my-secrets-configuration.sh b/custom-config-sample/my-secrets-configuration.sh
index 85cb98d..2c404dd 100644
--- a/custom-config-sample/my-secrets-configuration.sh
+++ b/custom-config-sample/my-secrets-configuration.sh
@@ -11,3 +11,8 @@ GITLAB_PRIVATE_TOKEN=__YOUR_GITLAB_TOKEN_HERE__
 #GITLAB_USER=__YOUR_GIT_USER__
 #GITLAB_PASSWORD=$(url_encode '__YOUR_GIT_USER_PASSWORD__')
 #GITLAB_CLONE_HTTP_PREFIX="https://${GITLAB_USER}:${GITLAB_PASSWORD}@${GITLAB_URL_PREFIX#"https://"}"
+
+# If client certificate is needed for HTTPS communication with GitLab server
+#GITLAB_CLIENT_CERTIFICATE=__PATH_TO_YOUR_CLIENT_CERTIFICATE__
+#GITLAB_CLIENT_CERTIFICATE_PASSWORD=__PASSWORD_FOR_YOUR_CLIENT_CERTIFICATE__
+#GITLAB_PRIVATE_KEY=__PATH_TO_YOUR_PRIVATE_KEY__