diff --git a/README.md b/README.md
index eb122917..0d942757 100644
--- a/README.md
+++ b/README.md
@@ -341,6 +341,7 @@ You don't have to do anything manually!
 1. Hurricane Electric DNS service (https://dns.he.net)
 1. UnoEuro API (https://www.unoeuro.com/)
 1. INWX (https://www.inwx.de/)
+1. Servercow (https://servercow.de)
 
 
 And: 
diff --git a/acme.sh b/acme.sh
index 88273cf5..472975a6 100755
--- a/acme.sh
+++ b/acme.sh
@@ -4308,7 +4308,12 @@ _installcert() {
     if [ -f "$_real_key" ] && [ ! "$IS_RENEW" ]; then
       cp "$_real_key" "$_backup_path/key.bak"
     fi
-    cat "$CERT_KEY_PATH" >"$_real_key"
+    if [ -f "$_real_key" ]; then
+      cat "$CERT_KEY_PATH" >"$_real_key"
+    else
+      cat "$CERT_KEY_PATH" >"$_real_key"
+      chmod 700 "$_real_key"
+    fi
   fi
 
   if [ "$_real_fullchain" ]; then
diff --git a/dnsapi/README.md b/dnsapi/README.md
index c16e7598..d357c053 100644
--- a/dnsapi/README.md
+++ b/dnsapi/README.md
@@ -635,6 +635,22 @@ acme.sh --issue --dns dns_inwx -d example.com -d www.example.com
 
 The `INWX_User` and `INWX_Password` settings will be saved in `~/.acme.sh/account.conf` and will be reused when needed.
 
+## 34. User Servercow API v1
+
+Create a new user from the servercow control center. Don't forget to activate **DNS API** for this user.
+
+```
+export SERVERCOW_API_Username=username
+export SERVERCOW_API_Password=password
+```
+
+Now you cann issue a cert:
+
+```
+acme.sh --issue --dns dns_servercow -d example.com -d www.example.com
+```
+Both, `SERVERCOW_API_Username` and `SERVERCOW_API_Password` will be saved in `~/.acme.sh/account.conf` and will be reused when needed.
+
 # Use custom API
 
 If your API is not supported yet, you can write your own DNS API.
diff --git a/dnsapi/dns_servercow.sh b/dnsapi/dns_servercow.sh
new file mode 100755
index 00000000..be4e59da
--- /dev/null
+++ b/dnsapi/dns_servercow.sh
@@ -0,0 +1,170 @@
+#!/usr/bin/env sh
+
+##########
+# Custom servercow.de DNS API v1 for use with [acme.sh](https://github.com/Neilpang/acme.sh)
+#
+# Usage:
+# export SERVERCOW_API_Username=username
+# export SERVERCOW_API_Password=password
+# acme.sh --issue -d example.com --dns dns_servercow
+#
+# Issues:
+# Any issues / questions / suggestions can be posted here:
+# https://github.com/jhartlep/servercow-dns-api/issues
+#
+# Author: Jens Hartlep
+##########
+
+SERVERCOW_API="https://api.servercow.de/dns/v1/domains"
+
+# Usage dns_servercow_add _acme-challenge.www.domain.com "abcdefghijklmnopqrstuvwxyz"
+dns_servercow_add() {
+  fulldomain=$1
+  txtvalue=$2
+
+  _info "Using servercow"
+  _debug fulldomain "$fulldomain"
+  _debug txtvalue "$txtvalue"
+
+  SERVERCOW_API_Username="${SERVERCOW_API_Username:-$(_readaccountconf_mutable SERVERCOW_API_Username)}"
+  SERVERCOW_API_Password="${SERVERCOW_API_Password:-$(_readaccountconf_mutable SERVERCOW_API_Password)}"
+  if [ -z "$SERVERCOW_API_Username" ] || [ -z "$SERVERCOW_API_Password" ]; then
+    SERVERCOW_API_Username=""
+    SERVERCOW_API_Password=""
+    _err "You don't specify servercow api username and password yet."
+    _err "Please create your username and password and try again."
+    return 1
+  fi
+
+  # save the credentials to the account conf file
+  _saveaccountconf_mutable SERVERCOW_API_Username "$SERVERCOW_API_Username"
+  _saveaccountconf_mutable SERVERCOW_API_Password "$SERVERCOW_API_Password"
+
+  _debug "First detect the root zone"
+  if ! _get_root "$fulldomain"; then
+    _err "invalid domain"
+    return 1
+  fi
+
+  _debug _sub_domain "$_sub_domain"
+  _debug _domain "$_domain"
+
+  if _servercow_api POST "$_domain" "{\"type\":\"TXT\",\"name\":\"$fulldomain\",\"content\":\"$txtvalue\",\"ttl\":20}"; then
+    if printf -- "%s" "$response" | grep "ok" >/dev/null; then
+      _info "Added, OK"
+      return 0
+    else
+      _err "add txt record error."
+      return 1
+    fi
+  fi
+  _err "add txt record error."
+
+  return 1
+}
+
+# Usage fulldomain txtvalue
+# Remove the txt record after validation
+dns_servercow_rm() {
+  fulldomain=$1
+  txtvalue=$2
+
+  _info "Using servercow"
+  _debug fulldomain "$fulldomain"
+  _debug txtvalue "$fulldomain"
+
+  SERVERCOW_API_Username="${SERVERCOW_API_Username:-$(_readaccountconf_mutable SERVERCOW_API_Username)}"
+  SERVERCOW_API_Password="${SERVERCOW_API_Password:-$(_readaccountconf_mutable SERVERCOW_API_Password)}"
+  if [ -z "$SERVERCOW_API_Username" ] || [ -z "$SERVERCOW_API_Password" ]; then
+    SERVERCOW_API_Username=""
+    SERVERCOW_API_Password=""
+    _err "You don't specify servercow api username and password yet."
+    _err "Please create your username and password and try again."
+    return 1
+  fi
+
+  _debug "First detect the root zone"
+  if ! _get_root "$fulldomain"; then
+    _err "invalid domain"
+    return 1
+  fi
+
+  _debug _sub_domain "$_sub_domain"
+  _debug _domain "$_domain"
+
+  if _servercow_api DELETE "$_domain" "{\"type\":\"TXT\",\"name\":\"$fulldomain\"}"; then
+    if printf -- "%s" "$response" | grep "ok" >/dev/null; then
+      _info "Deleted, OK"
+      _contains "$response" '"message":"ok"'
+    else
+      _err "delete txt record error."
+      return 1
+    fi
+  fi
+
+}
+
+####################  Private functions below ##################################
+
+# _acme-challenge.www.domain.com
+# returns
+#  _sub_domain=_acme-challenge.www
+#  _domain=domain.com
+_get_root() {
+  fulldomain=$1
+  i=2
+  p=1
+
+  while true; do
+    _domain=$(printf "%s" "$fulldomain" | cut -d . -f $i-100)
+
+    _debug _domain "$_domain"
+    if [ -z "$_domain" ]; then
+      # not valid
+      return 1
+    fi
+
+    if ! _servercow_api GET "$_domain"; then
+      return 1
+    fi
+
+    if ! _contains "$response" '"error":"no such domain in user context"' >/dev/null; then
+      _sub_domain=$(printf "%s" "$fulldomain" | cut -d . -f 1-$p)
+      if [ -z "$_sub_domain" ]; then
+        # not valid
+        return 1
+      fi
+
+      return 0
+    fi
+
+    p=$i
+    i=$(_math "$i" + 1)
+  done
+
+  return 1
+}
+
+_servercow_api() {
+  method=$1
+  domain=$2
+  data="$3"
+
+  export _H1="Content-Type: application/json"
+  export _H2="X-Auth-Username: $SERVERCOW_API_Username"
+  export _H3="X-Auth-Password: $SERVERCOW_API_Password"
+
+  if [ "$method" != "GET" ]; then
+    _debug data "$data"
+    response="$(_post "$data" "$SERVERCOW_API/$domain" "" "$method")"
+  else
+    response="$(_get "$SERVERCOW_API/$domain")"
+  fi
+
+  if [ "$?" != "0" ]; then
+    _err "error $domain"
+    return 1
+  fi
+  _debug2 response "$response"
+  return 0
+}