diff --git a/acme.sh b/acme.sh
index a5ac9e47..748e3f65 100755
--- a/acme.sh
+++ b/acme.sh
@@ -14,11 +14,12 @@ _WINDOWS_SCHEDULER_NAME="$PROJECT_NAME.cron"
 
 _SCRIPT_="$0"
 
+_SUB_FOLDER_COMMON="common"
 _SUB_FOLDER_NOTIFY="notify"
 _SUB_FOLDER_DNSAPI="dnsapi"
 _SUB_FOLDER_DEPLOY="deploy"
 
-_SUB_FOLDERS="$_SUB_FOLDER_DNSAPI $_SUB_FOLDER_DEPLOY $_SUB_FOLDER_NOTIFY"
+_SUB_FOLDERS="$_SUB_FOLDER_COMMON $_SUB_FOLDER_DNSAPI $_SUB_FOLDER_DEPLOY $_SUB_FOLDER_NOTIFY"
 
 CA_LETSENCRYPT_V1="https://acme-v01.api.letsencrypt.org/directory"
 
diff --git a/common/aws.sh b/common/aws.sh
new file mode 100644
index 00000000..2f83ccdf
--- /dev/null
+++ b/common/aws.sh
@@ -0,0 +1,197 @@
+#!/usr/bin/env sh
+
+# usage: _aws <svc> <svcargs...>
+#
+# services:
+#
+#   ACM: _aws acm <rpc> <region> [json]
+#        _aws acm ListCertificates us-east-1 '{"MaxItems": 2}'
+
+_aws() {
+  _svc="$1" # _args=...
+  shift
+  if ! _aws_auth; then
+    return 255
+  fi
+  n="$(printf '\nn')" n="${n%n}"
+  "_aws_svc_$_svc" "$@"
+}
+
+# private
+
+# services
+
+_aws_svc_acm() {
+  _rpc="$1" _region="$2" _json="$3"
+
+  _empty='{}'
+  _rpc="x-amz-target:CertificateManager.$_rpc"
+  _type='content-type:application/x-amz-json-1.1'
+
+  _aws_wrap '"__type":' \
+    POST "acm.$_region.amazonaws.com" '/' '' "$_region/acm" \
+    "$_rpc$n$_type" "${_json:-$_empty}"
+}
+
+# core
+
+_aws_wrap() {
+  _check="$1" # _args=...
+  shift
+  _resp="$(_aws_req4 "$@")"
+  _ret="$?"
+  _debug2 _resp "$_resp"
+  if [ "$_ret" -eq 0 ] && _contains "$_resp" "$_check"; then
+    _err "Response error: $_resp"
+    return 1
+  fi
+  printf %s "$_resp"
+  return "$_ret"
+}
+
+_aws_req4() {
+  _verb="$1" _host="$2" _path="$3" _query="$4" _svc="$5" _hdrs="$6" _data="$7"
+
+  _debug _verb "$_verb"
+  _debug _host "$_host"
+  _debug _path "$_path"
+  _debug _query "$_query"
+  _debug _svc "$_svc"
+  _debug _hdrs "$_hdrs"
+  _debug _data "$_data"
+
+  _date="$(date -u +%Y%m%dT%H%M%SZ)"
+  _debug2 _date "$_date"
+
+  _hdrs="host:$_host${n}x-amz-date:$_date$n$_hdrs"
+  if [ "$AWS_SESSION_TOKEN" ]; then
+    _hdrs="$_hdrs${n}x-amz-security-token:$AWS_SESSION_TOKEN"
+  fi
+  _hdrs="$(printf %s "$_hdrs" | sort | sed '/^$/d')$n"
+  _debug2 _hdrs "$_hdrs"
+
+  _keys="$(
+    printf %s "$_hdrs" | while read -r _hdr; do
+      printf '%s\n' "${_hdr%%:*}"
+    done | paste -sd ';'
+  )"
+  _debug2 _keys "$_keys"
+
+  _scope="$(printf %s "$_date" | cut -c 1-8)/$_svc/aws4_request"
+  _debug2 _scope "$_scope"
+
+  _hash='sha256'
+  _debug3 _hash "$_hash"
+  _algo='AWS4-HMAC-SHA256'
+  _debug3 _algo "$_algo"
+
+  _bdy="$(printf %s "$_data" | _digest "$_hash" hex)"
+  _debug2 _bdy "$_bdy"
+  _req="$_verb$n$_path$n$_query$n$_hdrs$n$_keys$n$_bdy"
+  _debug2 _req "$_req"
+  _req="$(printf %s "$_req" | _digest "$_hash" hex)"
+  _debug2 _req "$_req"
+  _str="$_algo$n$_date$n$_scope$n$_req"
+  _debug2 _str "$_str"
+
+  _sig="$(printf %s "AWS4$AWS_SECRET_ACCESS_KEY" | _hex_dump | tr -d ' ')"
+  _secure_debug2 _sig "$_sig"
+  for _step in $(printf %s "$_scope" | tr '/' ' ') "$_str"; do
+    _debug2 _step "$_step"
+    _sig="$(printf %s "$_step" | _hmac "$_hash" "$_sig" hex)"
+    _debug2 _sig "$_sig"
+  done
+
+  _cred="$AWS_ACCESS_KEY_ID/$_scope"
+  _auth="$_algo Credential=$_cred, SignedHeaders=$_keys, Signature=$_sig"
+  _debug2 _auth "$_auth"
+
+  _url="https://$_host$_path"
+  if [ "$_query" ]; then
+    _url="$_url?$_query"
+  fi
+
+  unset i
+  while read -r _line; do
+    i=$((i + 1))
+    eval "_H$i=\"\$_line\"; _debug2 _H$i \"\$_H$i\""
+  done <<-END
+		authorization:$_auth
+		$_hdrs
+	END
+
+  case "$(printf %s "$_verb" | tr '[:upper:]' '[:lower:]')" in
+  get) _get "$_url" ;;
+  post) _post "$_data" "$_url" ;;
+  *) _err '_aws only supports get and post' ;;
+  esac
+}
+
+# credentials
+
+_aws_auth() {
+  _aws_auth_environment || _aws_auth_container_role || _aws_auth_instance_role
+}
+
+_aws_auth_environment() {
+  AWS_ACCESS_KEY_ID="${AWS_ACCESS_KEY_ID:-$(_readaccountconf_mutable AWS_ACCESS_KEY_ID)}"
+  AWS_SECRET_ACCESS_KEY="${AWS_SECRET_ACCESS_KEY:-$(_readaccountconf_mutable AWS_SECRET_ACCESS_KEY)}"
+  if [ -z "$AWS_ACCESS_KEY_ID" ] || [ -z "$AWS_SECRET_ACCESS_KEY" ]; then
+    unset AWS_ACCESS_KEY_ID AWS_SECRET_ACCESS_KEY
+    return 1
+  fi
+  if [ -z "$_aws_using_role" ]; then
+    _saveaccountconf_mutable AWS_ACCESS_KEY_ID "$AWS_ACCESS_KEY_ID"
+    _saveaccountconf_mutable AWS_SECRET_ACCESS_KEY "$AWS_SECRET_ACCESS_KEY"
+  fi
+}
+
+_aws_auth_container_role() {
+  # automatically set if running inside ECS
+  if [ -z "$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI" ]; then
+    _debug 'no ECS environment variable detected'
+    return 1
+  fi
+  _aws_auth_metadata "169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI"
+}
+
+_aws_auth_instance_role() {
+  _url='http://169.254.169.254/latest/meta-data/iam/security-credentials/'
+  _debug _url "$_url"
+  _aws_role=$(_get "$_url" '' 1)
+  if [ "$?" -gt 0 ]; then
+    _debug 'unable to fetch IAM role from instance metadata'
+    return 1
+  fi
+  _debug _aws_role "$_aws_role"
+  _aws_auth_metadata "$_url$_aws_role"
+}
+
+_aws_auth_metadata() {
+  _url="$1"
+
+  _aws_creds="$(
+    _get "$_url" "" 1 |
+      _normalizeJson |
+      tr '{,}' '\n' |
+      while read -r _line; do
+        _key="$(printf %s "${_line%%:*}" | tr -d '"')" _value="${_line#*:}"
+        _debug3 _key "$_key"
+        _secure_debug3 _value "$_value"
+        case "$_key" in
+        AccessKeyId) printf '%s\n' "AWS_ACCESS_KEY_ID=$_value" ;;
+        SecretAccessKey) printf '%s\n' "AWS_SECRET_ACCESS_KEY=$_value" ;;
+        Token) printf '%s\n' "AWS_SESSION_TOKEN=$_value" ;;
+        esac
+      done |
+      paste -sd' ' -
+  )"
+  _secure_debug _aws_creds "$_aws_creds"
+
+  if [ -z "$_aws_creds" ]; then
+    return 1
+  fi
+
+  eval "$_aws_creds"
+  _aws_using_role=true
+}