diff --git a/dnsapi/dns_bergdns.sh b/dnsapi/dns_bergdns.sh
new file mode 100644
index 00000000..7c3e2864
--- /dev/null
+++ b/dnsapi/dns_bergdns.sh
@@ -0,0 +1,252 @@
+#!/usr/bin/env sh
+# shellcheck disable=SC2034
+dns_bergdns_info='bergdns.at
+Site: bergdns.at
+Docs: github.com/acmesh-official/acme.sh/wiki/dnsapi2#dns_bergdns
+Options:
+ BERGDNS_API_KEY API key, as issued in the account UI. Needs read (to find the zone and the record) and write over the challenge names.
+ BERGDNS_API_URL API base URL. Optional. Default "https://bergdns.at/v1".
+ BERGDNS_TTL TTL of the challenge record, in seconds. Optional. Default "60".
+ BERGDNS_PROPAGATION_TIMEOUT Seconds to wait for the record to reach every secondary. Optional. Default "120". "0" does not wait.
+Author: Kenny Kropp <https://github.com/kekropp>
+'
+
+_BERGDNS_DEFAULT_URL='https://bergdns.at/v1'
+_BERGDNS_DEFAULT_TTL='60'
+_BERGDNS_DEFAULT_WAIT='120'
+
+########  Public functions  ####################################################
+
+# Usage: dns_bergdns_add _acme-challenge.www.example.com "token"
+# The value is added to the RRset, so a domain and its wildcard can be
+# validated at the same time.
+dns_bergdns_add() {
+  fulldomain=$(echo "$1" | _lower_case)
+  txtvalue=$2
+
+  _bergdns_init || return 1
+  _bergdns_find_zone "$fulldomain" || return 1
+  _bergdns_find_rrset "$fulldomain" || return 1
+
+  _info "Adding TXT $fulldomain in zone $_bergdns_zone_name"
+  if [ -z "$_bergdns_rrset_id" ]; then
+    if _bergdns_rest POST "zones/$_bergdns_zone_id/rrsets" \
+      "{\"name\":\"$fulldomain\",\"type\":\"TXT\",\"ttl\":$BERGDNS_TTL,\"records\":[\"\\\"$txtvalue\\\"\"]}"; then
+      _bergdns_rrset_id=$(echo "$response" | _egrep_o '"id":"[^"]*"' | _head_n 1 | cut -d '"' -f 4)
+      _bergdns_wait "$fulldomain"
+      return 0
+    fi
+    if [ "$_bergdns_code" != "rrset_exists" ]; then
+      _err "bergdns: could not add the challenge record: $_bergdns_error"
+      return 1
+    fi
+    # another run created it since the lookup above
+    _bergdns_find_rrset "$fulldomain" || return 1
+    if [ -z "$_bergdns_rrset_id" ]; then
+      _err "bergdns: could not find the challenge record at $fulldomain"
+      return 1
+    fi
+  fi
+
+  if ! _bergdns_rest POST \
+    "zones/$_bergdns_zone_id/rrsets/$_bergdns_rrset_id/records" \
+    "{\"records\":[\"\\\"$txtvalue\\\"\"]}"; then
+    _err "bergdns: could not add the challenge record: $_bergdns_error"
+    return 1
+  fi
+
+  _bergdns_wait "$fulldomain"
+}
+
+# Usage: dns_bergdns_rm _acme-challenge.www.example.com "token"
+# Only this value is removed. Removing the last value deletes the RRset, and
+# removing a value that does not exist is not an error.
+dns_bergdns_rm() {
+  fulldomain=$(echo "$1" | _lower_case)
+  txtvalue=$2
+
+  _bergdns_init || return 1
+  _bergdns_find_zone "$fulldomain" || return 1
+  _bergdns_find_rrset "$fulldomain" || return 1
+
+  if [ -z "$_bergdns_rrset_id" ]; then
+    _info "bergdns: no TXT records at $fulldomain, nothing to remove"
+    return 0
+  fi
+
+  _info "Removing TXT $fulldomain from zone $_bergdns_zone_name"
+  if ! _bergdns_rest DELETE \
+    "zones/$_bergdns_zone_id/rrsets/$_bergdns_rrset_id/records" \
+    "{\"records\":[\"\\\"$txtvalue\\\"\"]}"; then
+    if [ "$_bergdns_code" = "rrset_not_found" ]; then
+      return 0
+    fi
+    _err "bergdns: could not remove the challenge record: $_bergdns_error"
+    return 1
+  fi
+  return 0
+}
+
+########  Private functions  ###################################################
+
+_bergdns_init() {
+  BERGDNS_API_KEY="${BERGDNS_API_KEY:-$(_readaccountconf_mutable BERGDNS_API_KEY)}"
+  BERGDNS_API_URL="${BERGDNS_API_URL:-$(_readaccountconf_mutable BERGDNS_API_URL)}"
+  BERGDNS_TTL="${BERGDNS_TTL:-$(_readaccountconf_mutable BERGDNS_TTL)}"
+  BERGDNS_PROPAGATION_TIMEOUT="${BERGDNS_PROPAGATION_TIMEOUT:-$(_readaccountconf_mutable BERGDNS_PROPAGATION_TIMEOUT)}"
+
+  if [ -z "$BERGDNS_API_KEY" ]; then
+    BERGDNS_API_KEY=""
+    _clearaccountconf_mutable BERGDNS_API_KEY
+    _err "You have not set BERGDNS_API_KEY. Create a key in the bergdns UI and export it:"
+    _err "  export BERGDNS_API_KEY=\"bgd_...\""
+    return 1
+  fi
+
+  [ -n "$BERGDNS_API_URL" ] || BERGDNS_API_URL="$_BERGDNS_DEFAULT_URL"
+  [ -n "$BERGDNS_TTL" ] || BERGDNS_TTL="$_BERGDNS_DEFAULT_TTL"
+  [ -n "$BERGDNS_PROPAGATION_TIMEOUT" ] || BERGDNS_PROPAGATION_TIMEOUT="$_BERGDNS_DEFAULT_WAIT"
+
+  # strip trailing slashes
+  BERGDNS_API_URL=$(echo "$BERGDNS_API_URL" | sed 's#/*$##')
+
+  _saveaccountconf_mutable BERGDNS_API_KEY "$BERGDNS_API_KEY"
+  _saveaccountconf_mutable BERGDNS_API_URL "$BERGDNS_API_URL"
+  _saveaccountconf_mutable BERGDNS_TTL "$BERGDNS_TTL"
+  _saveaccountconf_mutable BERGDNS_PROPAGATION_TIMEOUT "$BERGDNS_PROPAGATION_TIMEOUT"
+  return 0
+}
+
+# Usage: _bergdns_find_zone _acme-challenge.www.example.com
+# Sets _bergdns_zone_id and _bergdns_zone_name.
+# Zones are addressed by an id, not by name, so the zone list is fetched once
+# and the longest matching zone name wins.
+_bergdns_find_zone() {
+  _fqdn=$1
+  _bergdns_zone_id=""
+  _bergdns_zone_name=""
+
+  if ! _bergdns_rest GET "zones"; then
+    _err "bergdns: could not list zones: $_bergdns_error"
+    return 1
+  fi
+
+  # one zone object per line, so id and name stay together
+  _zone_lines=$(echo "$response" | tr '{' '\n' | grep '"name":"')
+
+  _candidate="$_fqdn"
+  while [ -n "$_candidate" ]; do
+    _line=$(echo "$_zone_lines" | grep -F "\"name\":\"$_candidate\"," | _head_n 1)
+    if [ -n "$_line" ]; then
+      _bergdns_zone_id=$(echo "$_line" | _egrep_o '"id":"[^"]*"' | _head_n 1 | cut -d '"' -f 4)
+      _bergdns_zone_name="$_candidate"
+      _debug _bergdns_zone_id "$_bergdns_zone_id"
+      _debug _bergdns_zone_name "$_bergdns_zone_name"
+      [ -n "$_bergdns_zone_id" ] && return 0
+      break
+    fi
+    case "$_candidate" in
+    *.*) _candidate=${_candidate#*.} ;;
+    *) _candidate="" ;;
+    esac
+  done
+
+  _err "bergdns: no zone in this account holds $_fqdn."
+  _err "bergdns: the key must be able to read the zone as well as write the record."
+  return 1
+}
+
+# Usage: _bergdns_find_rrset _acme-challenge.www.example.com
+# Sets _bergdns_rrset_id to the id of the TXT RRset at that name, or to an
+# empty string if there is none. Records are addressed by id, so the zone's
+# RRsets are listed to find it.
+_bergdns_find_rrset() {
+  _fqdn=$1
+  _bergdns_rrset_id=""
+
+  if ! _bergdns_rest GET "zones/$_bergdns_zone_id/rrsets"; then
+    _err "bergdns: could not list the records of $_bergdns_zone_name: $_bergdns_error"
+    return 1
+  fi
+
+  _line=$(echo "$response" | tr '{' '\n' | grep -F "\"name\":\"$_fqdn\",\"type\":\"TXT\"," | _head_n 1)
+  if [ -n "$_line" ]; then
+    _bergdns_rrset_id=$(echo "$_line" | _egrep_o '"id":"[^"]*"' | _head_n 1 | cut -d '"' -f 4)
+  fi
+  _debug _bergdns_rrset_id "$_bergdns_rrset_id"
+  return 0
+}
+
+# Usage: _bergdns_wait _acme-challenge.www.example.com
+# Polls the propagation endpoint until all bergdns nameservers serve the
+# record. A timeout is logged but does not fail the issuance.
+_bergdns_wait() {
+  _fqdn=$1
+  if [ "$BERGDNS_PROPAGATION_TIMEOUT" = "0" ] || [ -z "$_bergdns_rrset_id" ]; then
+    return 0
+  fi
+
+  _waited=0
+  while [ "$_waited" -lt "$BERGDNS_PROPAGATION_TIMEOUT" ]; do
+    if _bergdns_rest GET "zones/$_bergdns_zone_id/rrsets/$_bergdns_rrset_id/propagation"; then
+      case "$response" in
+      *'"propagated":true'*)
+        _info "bergdns: $_fqdn is served by every secondary after ${_waited}s"
+        return 0
+        ;;
+      esac
+    elif [ "$_bergdns_code" = "propagation_unavailable" ]; then
+      # propagation checks are not configured on this server
+      _info "bergdns: this deployment does not offer propagation checks; not waiting"
+      return 0
+    fi
+    _sleep 5
+    _waited=$((_waited + 5))
+  done
+
+  _info "bergdns: $_fqdn was not on every secondary after ${BERGDNS_PROPAGATION_TIMEOUT}s; continuing anyway"
+  return 0
+}
+
+# Usage: _bergdns_rest method endpoint [body]
+# Sets response. On failure also sets _bergdns_error and _bergdns_code.
+_bergdns_rest() {
+  _method=$1
+  _endpoint=$2
+  _body=$3
+  _bergdns_error=""
+  _bergdns_code=""
+
+  export _H1="Authorization: Bearer $BERGDNS_API_KEY"
+  export _H2="Accept: application/json"
+
+  _url="$BERGDNS_API_URL/$_endpoint"
+  _debug _url "$_url"
+
+  if [ "$_method" = "GET" ]; then
+    response="$(_get "$_url")"
+  else
+    _debug2 _body "$_body"
+    response="$(_post "$_body" "$_url" "" "$_method" "application/json")"
+  fi
+  _ret="$?"
+  _debug2 response "$response"
+
+  if [ "$_ret" != "0" ]; then
+    _bergdns_error="the request to $_url could not be made"
+    return 1
+  fi
+
+  # Errors are returned as RFC 9457 problem+json, which always has "status" and
+  # "code". Successful responses have neither, so the body is checked instead
+  # of the HTTP status code.
+  case "$response" in
+  *'"status":'*'"code":"'* | *'"code":"'*'"status":'*)
+    _bergdns_error=$(echo "$response" | sed -n 's/.*"detail":"\([^"]*\)".*/\1/p')
+    [ -n "$_bergdns_error" ] || _bergdns_error="$response"
+    _bergdns_code=$(echo "$response" | sed -n 's/.*"code":"\([^"]*\)".*/\1/p')
+    return 1
+    ;;
+  esac
+  return 0
+}