diff --git a/dnsapi/dns_sdns.sh b/dnsapi/dns_sdns.sh
new file mode 100644
index 00000000..581d3a3d
--- /dev/null
+++ b/dnsapi/dns_sdns.sh
@@ -0,0 +1,128 @@
+#!/usr/bin/env sh
+
+# s-dns is the Domain Name Registration System of Kyberio GmbH, former Hostway Deutschland GmbH
+
+# Steps to order a * certificate:
+# First log in into the domain robot, enable the dynamic DNS password for your zone and click save.
+
+# Copy the password and set the SDNS_ZONE_KEY variable with
+# export SDNS_ZONE_KEY=your_zone_key
+
+#
+# ./acme.sh --issue -d '*.www.domain.com'  --dns dns_sdns --server letsencrypt --dnssleep 240
+
+SDNS_API_URL="https://robot.s-dns.de:8488/"
+
+
+########  Public functions #####################
+
+# Adds a txt record with the specified value. Does not remove an existing record
+# Usage: dns_sdns_add  _acme-challenge.www.domain.com   "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
+dns_sdns_add() {
+  fulldomain=$1
+  txtvalue=$2
+  _debug2 "dns_sdns_add() entered"
+  SDNS_ZONE_KEY="${SDNS_ZONE_KEY:-$(_readaccountconf_mutable SDNS_ZONE_KEY)}"
+  if [ -z "$SDNS_ZONE_KEY" ]; then
+    SDNS_ZONE_KEY=""
+    _err "You didn't specify your zone key yet. (export SDNS_ZONE_KEY=yourkey)"
+    return 1
+  fi
+  _saveaccountconf_mutable SDNS_ZONE_KEY "$SDNS_ZONE_KEY"
+  _debug "First detect the root zone"
+  if ! _get_root "$fulldomain"; then
+    _err "invalid domain"
+    return 1
+  fi
+  _debug _sub_domain "$_sub_domain"
+  _debug _domain "$_domain"
+  _payload="<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>
+<zoneRequest>
+  <zone name=\"$_domain\" action=\"ADDORUPDATERR\" ddnskey=\"$SDNS_ZONE_KEY\">
+    <rr host=\"$_sub_domain\" type=\"TXT\" value=\"$txtvalue\" keepExisting=\"true\"/>
+  </zone>
+</zoneRequest>"
+  _debug2 "$_payload"
+  response=$(_post "$_payload" "$SDNS_API_URL")
+  _debug2 "$response"
+  if _contains "$response" "status=\"OK\""; then
+    _debug "The TXT record has been added."
+    return 0
+  else
+    _err "The attempt to add the TXT record has failed."
+    return 1
+  fi
+}
+
+# Removes a txt record with the specified value. This function does not remove resource records with the same name but a different values.
+# Usage: dns_sdns_rm  _acme-challenge.www.domain.com   "XKrxpRBosdIKFzxW_CT3KLZNf6q0HG9i01zxXp5CPBs"
+dns_sdns_rm() {
+  fulldomain=$1
+  txtvalue=$2
+  _debug2 "dns_sdns_rm() entered"
+  SDNS_ZONE_KEY="${SDNS_ZONE_KEY:-$(_readaccountconf_mutable SDNS_ZONE_KEY)}"
+  if [ -z "$SDNS_ZONE_KEY" ]; then
+    SDNS_ZONE_KEY=""
+    _err "You didn't specify your zone key yet. (export SDNS_ZONE_KEY=yourkey)"
+    return 1
+  fi
+  _saveaccountconf_mutable SDNS_ZONE_KEY "$SDNS_ZONE_KEY"
+  _debug "First detect the root zone"
+  if ! _get_root "$fulldomain"; then
+    _err "invalid domain"
+    return 1
+  fi
+  _debug _sub_domain "$_sub_domain"
+  _debug _domain "$_domain"
+  _payload="<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>
+<zoneRequest>
+  <zone name=\"$_domain\" action=\"DELRR\"  ddnskey=\"$SDNS_ZONE_KEY\">
+    <rr host=\"$_sub_domain\" type=\"TXT\" value=\"$txtvalue\" keepExisting=\"true\"/>
+  </zone>
+</zoneRequest>"
+  _debug "$_payload"
+  response=$(_post "$_payload" "$SDNS_API_URL")
+  _debug "$response"
+  if _contains "$response" "status=\"OK\""; then
+    _debug "The TXT record has been deleted."
+    return 0
+  else
+    _err "The attempt to delete the TXT record has failed."
+    return 1
+  fi
+}
+
+####################  Private functions below ##################################
+#_acme-challenge.www.domain.com
+
+#returns
+# _sub_domain=_acme-challenge.www
+# _domain=domain.com
+_get_root() {
+  fulldomain=$1
+  _debug2 "_get_root() entered"
+  SDNS_ZONE_KEY="${SDNS_ZONE_KEY:-$(_readaccountconf_mutable SDNS_ZONE_KEY)}"
+  if [ -z "$SDNS_ZONE_KEY" ]; then
+    SDNS_ZONE_KEY=""
+    _err "You didn't specify your zone key yet. (export SDNS_ZONE_KEY=yourkey)"
+    return 1
+  fi
+  _saveaccountconf_mutable SDNS_ZONE_KEY "$SDNS_ZONE_KEY"
+  _payload="<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>
+<zoneRequest action=\"getRootZone\" ddnskey=\"$SDNS_ZONE_KEY\">
+  <hostname>$fulldomain</hostname>
+</zoneRequest>"
+  _debug2 "$_payload"
+  response=$(_post "$_payload" "$SDNS_API_URL")
+  _debug2 "$response"
+  if _contains "$response" "status=\"found\""; then
+    _debug "root domain is found"
+
+    _domain=$(printf "%s\n" "$response" | _egrep_o "<zonename>(.*)</zonename>" | cut -d ">" -f 2 | cut -d "<" -f 1)
+    _sub_domain=$(printf "%s\n" "$response" | _egrep_o "<hostname>(.*)</hostname>" | cut -d ">" -f 2 | cut -d "<" -f 1)
+
+    _debug _domain "$_domain"
+    _debug _sub_domain "$_sub_domain"
+    return 0
+  fi
+}