diff --git a/dnsapi/dns_cyon.sh b/dnsapi/dns_cyon.sh
new file mode 100644
index 00000000..95e690bb
--- /dev/null
+++ b/dnsapi/dns_cyon.sh
@@ -0,0 +1,355 @@
+#!/usr/bin/env sh
+
+########
+# Custom cyon.ch DNS API for use with [acme.sh](https://github.com/Neilpang/acme.sh)
+#
+# Usage: acme.sh --issue --dns dns_cyon -d www.domain.com
+#
+# Dependencies:
+# -------------
+# - jq (get it here: https://stedolan.github.io/jq/download)
+# - oathtool (When using 2 Factor Authentication)
+#
+# Author: Armando Lüscher <armando@noplanman.ch>
+########
+
+########
+# Define cyon.ch login credentials:
+#
+# Either set them here: (uncomment these lines)
+#
+# cyon_username='your_cyon_username'
+# cyon_password='your_cyon_password'
+# cyon_otp_secret='your_otp_secret' # Only required if using 2FA
+#
+# ...or export them as environment variables in your shell:
+#
+# $ export cyon_username='your_cyon_username'
+# $ export cyon_password='your_cyon_password'
+# $ export cyon_otp_secret='your_otp_secret' # Only required if using 2FA
+#
+# *Note:*
+# After the first run, the credentials are saved in the "account.conf"
+# file, so any hard-coded or environment variables can then be removed.
+########
+
+dns_cyon_add() {
+  if ! _exists jq; then
+    _fail "Please install jq to use cyon.ch DNS API."
+  fi
+
+  _load_credentials
+  _load_parameters "$@"
+
+  _info_header "add"
+  _login
+  _domain_env
+  _add_txt
+  _cleanup
+
+  return 0
+}
+
+dns_cyon_rm() {
+  _load_credentials
+  _load_parameters "$@"
+
+  _info_header "delete"
+  _login
+  _domain_env
+  _delete_txt
+  _cleanup
+
+  return 0
+}
+
+#########################
+### PRIVATE FUNCTIONS ###
+#########################
+
+_load_credentials() {
+  # Convert loaded password to/from base64 as needed.
+  if [ "${cyon_password_b64}" ] ; then
+    cyon_password="$(echo "${cyon_password_b64}" | _dbase64)"
+  elif [ "${cyon_password}" ] ; then
+    cyon_password_b64="$(echo "${cyon_password}" | _base64)"
+  fi
+
+  if [ -z "${cyon_username}" ] || [ -z "${cyon_password}" ] ; then
+    _err ""
+    _err "You haven't set your cyon.ch login credentials yet."
+    _err "Please set the required cyon environment variables."
+    _err ""
+    exit 1
+  fi
+
+  # Save the login credentials to the account.conf file.
+  _debug "Save credentials to account.conf"
+  _saveaccountconf cyon_username "${cyon_username}"
+  _saveaccountconf cyon_password_b64 "$cyon_password_b64"
+  if [ ! -z "${cyon_otp_secret}" ] ; then
+    _saveaccountconf cyon_otp_secret "$cyon_otp_secret"
+  fi
+}
+
+_is_idn() {
+  _idn_temp=$(printf "%s" "$1" | tr -d "[0-9a-zA-Z.,-]")
+  _idn_temp2="$(printf "%s" "$1" | grep -o "xn--")"
+  [ "$_idn_temp" ] || [ "$_idn_temp2" ]
+}
+
+_load_parameters() {
+  # Read the required parameters to add the TXT entry.
+  fulldomain="$(echo "$1" | tr '[:upper:]' '[:lower:]')"
+  fulldomain_idn="${fulldomain}"
+
+  # Special case for IDNs, as cyon needs a domain environment change,
+  # which uses the "pretty" instead of the punycode version.
+  if _is_idn "$1" ; then
+    if ! _exists idn; then
+      _fail "Please install idn to process IDN names."
+    fi
+
+    fulldomain="$(idn -u "${fulldomain}")"
+    fulldomain_idn="$(idn -a "${fulldomain}")"
+  fi
+
+  _debug fulldomain "$fulldomain"
+  _debug fulldomain_idn "$fulldomain_idn"
+
+  txtvalue="$2"
+  _debug txtvalue "$txtvalue"
+
+  # Cookiejar required for login session, as cyon.ch has no official API (yet).
+  cookiejar=$(tempfile)
+  _debug cookiejar "$cookiejar"
+}
+
+_info_header() {
+  if [ "$1" = "add" ]; then
+    _info ""
+    _info "+---------------------------------------------+"
+    _info "| Adding DNS TXT entry to your cyon.ch domain |"
+    _info "+---------------------------------------------+"
+    _info ""
+    _info "  * Full Domain: ${fulldomain}"
+    _info "  * TXT Value:   ${txtvalue}"
+    _info "  * Cookie Jar:  ${cookiejar}"
+    _info ""
+  elif [ "$1" = "delete" ]; then
+    _info ""
+    _info "+-------------------------------------------------+"
+    _info "| Deleting DNS TXT entry from your cyon.ch domain |"
+    _info "+-------------------------------------------------+"
+    _info ""
+    _info "  * Full Domain: ${fulldomain}"
+    _info "  * Cookie Jar:  ${cookiejar}"
+    _info ""
+  fi
+}
+
+_login() {
+  _info "  - Logging in..."
+  login_response=$(curl \
+    "https://my.cyon.ch/auth/index/dologin-async" \
+    -s \
+    -c "${cookiejar}" \
+    -H "X-Requested-With: XMLHttpRequest" \
+    --data-urlencode "username=${cyon_username}" \
+    --data-urlencode "password=${cyon_password}" \
+    --data-urlencode "pathname=/")
+
+  _debug login_response "${login_response}"
+
+  # Bail if login fails.
+  if [ "$(echo "${login_response}" | jq -r '.onSuccess')" != "success" ]; then
+    _fail "    $(echo "${login_response}" | jq -r '.message')"
+  fi
+
+  _info "    success"
+
+
+  # NECESSARY!! Load the main page after login, before the OTP check.
+  curl "https://my.cyon.ch/" -s --compressed -b "${cookiejar}" >/dev/null
+
+
+  # todo: instead of just checking if the env variable is defined, check if we actually need to do a 2FA auth request.
+
+
+  # 2FA authentication with OTP?
+  if [ ! -z "${cyon_otp_secret}" ] ; then
+    _info "  - Authorising with OTP code..."
+
+    if ! _exists oathtool; then
+      _fail "Please install oathtool to use 2 Factor Authentication."
+    fi
+
+    # Get OTP code with the defined secret.
+    otp_code=$(oathtool --base32 --totp "${cyon_otp_secret}" 2>/dev/null)
+
+    otp_response=$(curl \
+      "https://my.cyon.ch/auth/multi-factor/domultifactorauth-async" \
+      -s \
+      --compressed \
+      -b "${cookiejar}" \
+      -c "${cookiejar}" \
+      -H "X-Requested-With: XMLHttpRequest" \
+      -d "totpcode=${otp_code}&pathname=%2F&rememberme=0")
+
+    _debug otp_response "${otp_response}"
+
+    # Bail if OTP authentication fails.
+    if [ "$(echo "${otp_response}" | jq -r '.onSuccess')" != "success" ]; then
+      _fail "    $(echo "${otp_response}" | jq -r '.message')"
+    fi
+
+    _info "    success"
+  fi
+
+  _info ""
+}
+
+_domain_env() {
+  _info "  - Changing domain environment..."
+
+  # Get the "example.com" part of the full domain name.
+  domain_env=$(echo "${fulldomain}" | sed -E -e 's/.*\.(.*\..*)$/\1/')
+  _debug "Changing domain environment to ${domain_env}"
+
+  domain_env_response=$(curl \
+    "https://my.cyon.ch/user/environment/setdomain/d/${domain_env}/gik/domain%3A${domain_env}" \
+    -s \
+    --compressed \
+    -b "${cookiejar}" \
+    -H "X-Requested-With: XMLHttpRequest")
+
+  _debug domain_env_response "${domain_env_response}"
+
+  _check_2fa_miss "${domain_env_response}"
+
+  domain_env_success=$(echo "${domain_env_response}" | jq -r '.authenticated')
+
+  # Bail if domain environment change fails.
+  if [ "${domain_env_success}" != "true" ]; then
+    _fail "    $(echo "${domain_env_response}" | jq -r '.message')"
+  fi
+
+  _info "    success"
+  _info ""
+}
+
+_add_txt() {
+  _info "  - Adding DNS TXT entry..."
+  addtxt_response=$(curl \
+    "https://my.cyon.ch/domain/dnseditor/add-record-async" \
+    -s \
+    --compressed \
+    -b "${cookiejar}" \
+    -H "X-Requested-With: XMLHttpRequest" \
+    -d "zone=${fulldomain_idn}.&ttl=900&type=TXT&value=${txtvalue}")
+
+  _debug addtxt_response "${addtxt_response}"
+
+  _check_2fa_miss "${addtxt_response}"
+
+  addtxt_message=$(echo "${addtxt_response}" | jq -r '.message')
+  addtxt_status=$(echo "${addtxt_response}" | jq -r '.status')
+
+  # Bail if adding TXT entry fails.
+  if [ "${addtxt_status}" != "true" ]; then
+    if [ "${addtxt_status}" = "null" ]; then
+      addtxt_message=$(echo "${addtxt_response}" | jq -r '.error.message')
+    fi
+    _fail "    ${addtxt_message}"
+  fi
+
+  _info "    success"
+  _info ""
+}
+
+_delete_txt() {
+  _info "  - Deleting DNS TXT entry..."
+
+  list_txt_response=$(curl \
+    "https://my.cyon.ch/domain/dnseditor/list-async" \
+    -s \
+    -b "${cookiejar}" \
+    --compressed \
+    -H "X-Requested-With: XMLHttpRequest")
+
+  _debug list_txt_response "${list_txt_response}"
+
+  _check_2fa_miss "${list_txt_response}"
+
+  # Find and delete all acme challenge entries for the $fulldomain.
+  _dns_entries=$(echo "$list_txt_response" | jq -r --arg fulldomain_idn "${fulldomain_idn}." '
+    .rows[] |
+      label $out|
+      if .[0] != $fulldomain_idn then
+        break $out
+      else
+        .[4]|
+        capture("data-hash=\"(?<hash>[^\"]*)\" data-identifier=\"(?<identifier>[^\"]*)\"";"g")|
+        .hash + " " + .identifier
+    end')
+  _dns_entries_cnt=$(echo "${_dns_entries}" | wc -l | grep -o '\d')
+
+  _info "    (entries found: ${_dns_entries_cnt})"
+
+  _dns_entry_num=0
+
+  echo "${_dns_entries}" | while read -r _hash _identifier
+  do
+    ((_dns_entry_num++))
+
+    delete_txt_response=$(curl \
+      "https://my.cyon.ch/domain/dnseditor/delete-record-async" \
+      -s \
+      --compressed \
+      -b "${cookiejar}" \
+      -H "X-Requested-With: XMLHttpRequest" \
+      --data-urlencode "hash=${_hash}" \
+      --data-urlencode "identifier=${_identifier}")
+
+    _debug delete_txt_response "${delete_txt_response}"
+
+    _check_2fa_miss "${delete_txt_response}"
+
+    delete_txt_message=$(echo "${delete_txt_response}" | jq -r '.message')
+    delete_txt_status=$(echo "${delete_txt_response}" | jq -r '.status')
+
+    # Skip if deleting TXT entry fails.
+    if [ "${delete_txt_status}" != "true" ]; then
+      if [ "${delete_txt_status}" = "null" ]; then
+        delete_txt_message=$(echo "${delete_txt_response}" | jq -r '.error.message')
+      fi
+      _err "    [${_dns_entry_num}/${_dns_entries_cnt}] ${delete_txt_message} (${_identifier})"
+    else
+      _info "    [${_dns_entry_num}/${_dns_entries_cnt}] success (${_identifier})"
+    fi
+  done
+
+  _info "    done"
+  _info ""
+}
+
+_check_2fa_miss() {
+  # Did we miss the 2FA?
+  if [[ "$1" =~ "multi_factor_form" ]] ; then
+    _fail "    Missed OTP authentication!"
+  fi
+}
+
+_fail() {
+  _err "$1"
+  _err ""
+  _cleanup
+  exit 1
+}
+
+_cleanup() {
+  _info "  - Cleanup."
+  _debug "Remove cookie jar: ${cookiejar}"
+  rm "${cookiejar}" 2>/dev/null
+  _info ""
+}