diff --git a/placeholder.sh b/placeholder.sh
new file mode 100755
index 0000000..5d054cc
--- /dev/null
+++ b/placeholder.sh
@@ -0,0 +1,175 @@
+#!/bin/bash
+set -e
+LENGTH=$(head -c 4 | perl -ne 'print unpack("L", $_)')
+declare -gr REQUEST=$(head -c $LENGTH)
+VERSION=3000000
+
+# Write a number as little-endian binary
+function writelen()
+{
+    printf
+}
+
+# Require a command to be present, and quit if it's not
+function require()
+{
+    if ! `command -v "$1" >/dev/null`; then
+        OUTPUT="{\n  \"status\": \"error\"\n  "version": $VERSION,\n  \"message\": \"Required dependency '$1' is missing\"\n  \"code\": 1\n}"
+        LANG=C LC_ALL=C LENGTH=${#OUTPUT}
+        echo -n 
+        exit 1
+    fi
+}
+
+# Echo to stderr with failure status code
+function fail()
+{
+    echo "$@" >&2
+    return 1
+}
+
+# trim leading and trailing whitespace
+function trim()
+{
+    echo "$1" | sed 's/^[[:space:]]*//' | sed 's/[[:space:]]*$//'
+}
+
+# Build an error response message
+function error()
+{
+    if [ -n "$1" ]; then
+        ERROR="$1"
+    else
+        ERROR=$(cat)
+    fi
+    [ -n "$2" ] && CODE="$2" || CODE=1
+    OUTPUT="$(jq -n '.status = "error"' | jq --arg message "$ERROR" --arg code "$CODE" '.message = $message | .code = ($code|tonumber)')"
+    perl -e "print pack('L', ${#OUTPUT})"
+    echo -n "$OUTPUT"
+}
+
+# Wrap a shell command and bail with a valid response message on error
+function wrap()
+{
+    . <({ STDERR=$({ STDOUT=$("$@"); EXIT=$?; } 2>&1; declare -p EXIT >&2; declare -p STDOUT >&2); declare -p STDERR; } 2>&1; )
+    if [ $EXIT -gt 0 ] || [ -n "$STDERR" ]; then
+        if [ -n "$STDERR" ]; then
+            echo -n "$STDERR" | error
+        elif [ -n "$STDOUT" ]; then
+            echo -n "$STDOUT" | error
+        else
+            error "$@" $EXIT
+        fi
+    else
+        OUTPUT="$(jq -n --arg version $VERSION --arg response "$STDOUT" '.status = "ok" | .version = $version | .response = ($response | if .[:1] == "{" then ( . | fromjson) else . end)')"
+        perl -e "print pack('L', ${#OUTPUT})"
+        echo -n "$OUTPUT"
+    fi
+    return $EXIT
+}
+
+# jq wrapper around the request
+function rq()
+{
+    jq -r "$@" <<< "$REQUEST"
+}
+
+# Supply per-store configuration
+function configure()
+{
+    set -e
+
+    declare -A STORES
+    . <(rq '.settings.stores | to_entries | map("STORES[\(.key|@sh)]=\(.value.path|@sh)")[]')
+
+    for STORE in "${!STORES[@]}"; do
+        STOREPATH=$(echo "${STORES["$STORE"]}" | sed 's/^~/$HOME/' | envsubst)
+        [ -d "$STOREPATH" ] || fail "Store directory for '$STORE' does not exist: $STOREPATH"
+
+        if [ -f "$STOREPATH/.browserpass.json" ]; then
+            STORES["$STORE"]=$(cat "$STOREPATH/.browserpass.json")
+        else
+            STORES["$STORE"]=
+        fi
+    done
+
+    OUTPUT='{}'
+    for STORE in "${!STORES[@]}"; do
+        OUTPUT=$(jq --arg store "$STORE" --arg settings "${STORES[$STORE]}" '.storeSettings[$store] = $settings' <<< "$OUTPUT")
+    done
+
+    echo "$OUTPUT"
+}
+
+# List all available logins by store
+function list()
+{
+    set -e
+
+    declare -A STORES
+    . <(rq '.settings.stores | to_entries | map("STORES[\(.key|@sh)]=\(.value.path|@sh)")[]')
+    for STORE in "${!STORES[@]}"; do
+        STOREPATH=$(echo "${STORES["$STORE"]}" | sed 's/^~/$HOME/' | envsubst)
+        [ -d "$STOREPATH" ] || fail "Store directory for '$STORE' does not exist: $STOREPATH"
+
+        STORES[$STORE]="$(find -L "$STOREPATH" -type f -name '*.gpg' -printf '%P\n' | jq -R -s 'split("\n") | map(select(length > 0)) ')"
+    done
+
+    OUTPUT='{}'
+    for STORE in "${!STORES[@]}"; do
+        OUTPUT=$(jq --arg store "$STORE" --arg files "${STORES[$STORE]}" '.files[$store] = ($files|fromjson)' <<< "$OUTPUT")
+    done
+
+    echo "$OUTPUT"
+}
+
+# Fetch the specified fields from a single login
+function fetch()
+{
+    set -e
+
+    STORE="$(rq .store)"
+    FILE="$(rq .file)"
+
+    # sanity-check variables
+    [ -n "$STORE" ] || fail ".store is not set"
+    [ -n "$FILE" ] || fail ".file is not set"
+
+    # get file path
+    STOREPATH="$(rq --arg store "$STORE" '.settings.stores[$store].path//empty' | sed 's/^~/$HOME/' | envsubst)"
+    [ -n "$STOREPATH" ] || fail "Store path is empty"
+    [ -d "$STOREPATH" ] || fail "Store directory for '$STORE' does not exist: $STOREPATH"
+    FILEPATH="$STOREPATH/$FILE"
+
+    # get file contents
+    [ -f "$FILEPATH" ] || fail "Requested file does not exist: $STORE:$FILE"
+    DATA="$(gpg -q --decrypt "$FILEPATH")"
+    
+    # build output
+    echo "$(jq -n --arg data "$DATA" '.data = $data')"
+}
+
+function run()
+{
+    case "$(rq .action)" in
+        configure)  configure; return $?;;
+        list)       list; return $?;;
+        fetch)      fetch; return $?;;
+        *)          echo "Unknown action: $(rq .action)" >&2; return 1;;
+    esac
+}
+
+# Ensure dependencies are present
+require cat
+require envsubst
+require find
+require gpg
+require grep
+require head
+require jq
+require perl
+require sed
+require tac
+
+# Run the client
+wrap run