diff --git a/notify/mattermost.sh b/notify/mattermost.sh
new file mode 100644
index 00000000..9037ae0d
--- /dev/null
+++ b/notify/mattermost.sh
@@ -0,0 +1,52 @@
+#!/usr/bin/env sh
+
+# Support mattermost bots
+
+#MATTERMOST_API_URL=""
+#MATTERMOST_CHANNEL_ID=""
+#MATTERMOST_BOT_TOKEN=""
+
+mattermost_send() {
+  _subject="$1"
+  _content="$2"
+  _statusCode="$3" #0: success, 1: error 2($RENEW_SKIP): skipped
+  _debug "_statusCode" "$_statusCode"
+
+  MATTERMOST_API_URL="${MATTERMOST_API_URL:-$(_readaccountconf_mutable MATTERMOST_API_URL)}"
+  if [ -z "$MATTERMOST_API_URL" ]; then
+    _err "You didn't specify a Mattermost API URL MATTERMOST_API_URL yet."
+    return 1
+  fi
+  _saveaccountconf_mutable MATTERMOST_API_URL "$MATTERMOST_API_URL"
+
+  MATTERMOST_CHANNEL_ID="${MATTERMOST_CHANNEL_ID:-$(_readaccountconf_mutable MATTERMOST_CHANNEL_ID)}"
+  if [ -z "$MATTERMOST_CHANNEL_ID" ]; then
+    _err "You didn't specify a Mattermost channel id MATTERMOST_CHANNEL_ID yet."
+    return 1
+  fi
+  _saveaccountconf_mutable MATTERMOST_CHANNEL_ID "$MATTERMOST_CHANNEL_ID"
+
+  MATTERMOST_BOT_TOKEN="${MATTERMOST_BOT_TOKEN:-$(_readaccountconf_mutable MATTERMOST_BOT_TOKEN)}"
+  if [ -z "$MATTERMOST_BOT_TOKEN" ]; then
+    _err "You didn't specify a Mattermost bot API token MATTERMOST_BOT_TOKEN yet."
+    return 1
+  fi
+  _saveaccountconf_mutable MATTERMOST_BOT_TOKEN "$MATTERMOST_BOT_TOKEN"
+
+  _content="$(printf "*%s*\n%s" "$_subject" "$_content" | _json_encode)"
+  _data="{\"channel_id\": \"$MATTERMOST_CHANNEL_ID\", "
+  _data="$_data\"message\": \"$_content\"}"
+
+  export _H1="Authorization: Bearer $MATTERMOST_BOT_TOKEN"
+
+  if _post "$_data" "$MATTERMOST_API_URL" "" "POST" "application/json; charset=utf-8"; then
+    MATTERMOST_RESULT_OK=$(echo "$response" | _egrep_o 'create_at')
+    if [ "$?" = "0" ] && [ "$MATTERMOST_RESULT_OK" ]; then
+      _info "mattermost send success."
+      return 0
+    fi
+  fi
+  _err "mattermost send error."
+  _err "$response"
+  return 1
+}