diff --git a/client/Cargo.toml b/client/Cargo.toml
new file mode 100644
index 0000000..e2f1a1e
--- /dev/null
+++ b/client/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "navka-client"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio        = { version = "1", features = ["rt-multi-thread", "macros"] }
+navka-common = { path = "../common" }
+evdev        = "0.12"
+tonic        = "0.11"
diff --git a/client/src/main.rs b/client/src/main.rs
new file mode 100644
index 0000000..3485a98
--- /dev/null
+++ b/client/src/main.rs
@@ -0,0 +1,32 @@
+use evdev::{Device, InputEventKind};
+use navka_common::navka::{relay_client::RelayClient, HidReport};
+use tonic::transport::Channel;
+
+const KEYBOARD: &str = "/dev/input/event4";        // adjust
+const NAVKA_IP: &str = "192.168.42.253:4000";
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    // open evdev
+    let mut dev = Device::open(KEYBOARD)?;
+
+    // connect to navka
+    let channel = Channel::from_shared(format!("http://{NAVKA_IP}"))?
+        .connect().await?;
+    let (mut tx, _rx) = RelayClient::new(channel).stream().await?.into_inner();
+
+    loop {
+        for ev in dev.fetch_events()? {
+            if let InputEventKind::Key(code) = ev.kind() {
+                // simple map: only letters a-z for PoC
+                let usage = match code.0 {
+                    30..=55 => (code.0 - 26) as u8,     // HID usage 0x04..0x1d
+                    _ => continue,
+                };
+                let mut buf = [0u8; 8];
+                buf[2] = if ev.value() == 1 { usage } else { 0 };
+                tx.send(HidReport { data: buf.to_vec() }).await?;
+            }
+        }
+    }
+}
diff --git a/common/Cargo.toml b/common/Cargo.toml
new file mode 100644
index 0000000..9438985
--- /dev/null
+++ b/common/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "navka-common"
+version = "0.1.0"
+edition = "2021"
+build   = "build.rs"
+
+[dependencies]
+tonic   = "0.11"
+prost   = "0.12"
+
+[build-dependencies]
+tonic-build = "0.11"
diff --git a/common/build.rs b/common/build.rs
new file mode 100644
index 0000000..b713560
--- /dev/null
+++ b/common/build.rs
@@ -0,0 +1,8 @@
+fn main() {
+    tonic_build::configure()
+        .build_client(true)
+        .build_server(true)
+        .out_dir("src/")
+        .compile(&["proto/navka.proto"], &["proto"])
+        .unwrap();
+}
diff --git a/common/navka.proto b/common/navka.proto
new file mode 100644
index 0000000..cf1f202
--- /dev/null
+++ b/common/navka.proto
@@ -0,0 +1,8 @@
+syntax = "proto3";
+package navka;
+
+message HidReport { bytes data = 1; }
+
+service Relay {
+  rpc Stream (stream HidReport) returns (stream HidReport);
+}
diff --git a/install-navka-relay.sh b/install-navka-relay.sh
deleted file mode 100755
index 73714c8..0000000
--- a/install-navka-relay.sh
+++ /dev/null
@@ -1,76 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-# ---------- paths ----------
-SRC_DIR=$(pwd)                 # where the script is launched
-APPDIR=/opt/navka-relay
-VENV=$APPDIR/venv
-SERVICE=$HOME/.config/systemd/user/navka-relay.service
-USR=${SUDO_USER:-$USER}
-
-green(){ printf '\e[1;32m==>\e[0m %s\n' "$*"; }
-
-##############################################################################
-green "1.  Packages (python + evdev) …"
-##############################################################################
-sudo pacman -Sy --needed --noconfirm python python-evdev >/dev/null
-
-##############################################################################
-green "2.  Install /opt/navka-relay …"
-##############################################################################
-sudo mkdir -p "$APPDIR"
-sudo chown "$USR":"$USR" "$APPDIR"
-
-# use a symlink when run from dev folder so edits are live
-if [[ $SRC_DIR != "$APPDIR" ]]; then
-  ln -sf "$SRC_DIR/navka-relay.sh" "$APPDIR/navka-relay.sh"
-fi
-chmod +x "$SRC_DIR/navka-relay.sh"
-
-##############################################################################
-green "3.  Build virtual-env (system pkgs visible) …"
-##############################################################################
-if [[ ! -d $VENV/bin ]]; then
-  python -m venv --system-site-packages "$VENV"
-fi
-
-# ensure evdev importable inside venv (pacman pkg provides it; pip fallback)
-"$VENV/bin/pip" install --quiet --disable-pip-version-check --upgrade pip >/dev/null
-"$VENV/bin/python" - <<'PY'
-import importlib, subprocess, sys
-try:
-    importlib.import_module('evdev')
-except ImportError:
-    subprocess.check_call([sys.executable, '-m', 'pip', 'install', 'evdev'])
-PY
-
-##############################################################################
-green "4.  systemd *user* unit …"
-##############################################################################
-mkdir -p "$(dirname "$SERVICE")"
-cat >"$SERVICE" <<EOF
-[Unit]
-Description=Navka keyboard relay
-After=network.target
-
-[Service]
-Type=simple
-ExecStart=/opt/navka-relay/navka-relay.sh
-Restart=on-failure
-EnvironmentFile=%h/.config/navka-relay.env
-
-[Install]
-WantedBy=default.target
-EOF
-
-systemctl --user daemon-reload
-systemctl --user enable navka-relay >/dev/null 2>&1 || true
-
-green "✔  Install complete"
-cat <<'TXT'
-Start relay : systemctl --user start navka-relay
-Stop relay  : systemctl --user stop  navka-relay
-Manual run  : /opt/navka-relay/navka-relay.sh
-Variables   : NAVKA_IP=… NAVKA_PORT=… NAVKA_KBD=… navka-relay.sh
-TXT
-
diff --git a/navka-relay.sh b/navka-relay.sh
deleted file mode 100755
index 2f9cf1b..0000000
--- a/navka-relay.sh
+++ /dev/null
@@ -1,74 +0,0 @@
-#!/usr/bin/env bash
-# Wrapper that activates local venv then executes embedded Python
-
-DIR=$(dirname "$(readlink -f "$0")")
-VENV=/opt/navka-relay/venv
-PY="$VENV/bin/python"
-
-if [[ ! -x $PY ]]; then
-  echo "❌  venv missing: run install-navka-relay.sh first." >&2
-  exit 1
-fi
-
-# shellcheck disable=SC2091
-exec $PY - <<'PYCODE'
-import os, socket, selectors, signal, sys
-from evdev import InputDevice, ecodes
-
-# --------- config via env ----------
-DEV   = os.getenv("NAVKA_KBD", "/dev/input/event4")
-IP    = os.getenv("NAVKA_IP",  "192.168.42.253")
-PORT  = int(os.getenv("NAVKA_PORT", "4000"))
-# -----------------------------------
-
-# full HID tables (letters, numbers, F1-F12, arrows, etc.)
-HID = {**{getattr(ecodes,f"KEY_F{i}"):i+53 for i in range(1,13)}}
-for ev,h in {
-  **{k:4+i for i,k in enumerate(range(ecodes.KEY_A,ecodes.KEY_Z+1))},
-  **{k:30+i for i,k in enumerate(range(ecodes.KEY_1,ecodes.KEY_0+1))},
-  ecodes.KEY_ENTER:40, ecodes.KEY_ESC:41, ecodes.KEY_BACKSPACE:42,
-  ecodes.KEY_TAB:43,  ecodes.KEY_SPACE:44, ecodes.KEY_MINUS:45,
-  ecodes.KEY_EQUAL:46, ecodes.KEY_LEFTBRACE:47, ecodes.KEY_RIGHTBRACE:48,
-  ecodes.KEY_BACKSLASH:49, ecodes.KEY_SEMICOLON:51, ecodes.KEY_APOSTROPHE:52,
-  ecodes.KEY_GRAVE:53, ecodes.KEY_COMMA:54, ecodes.KEY_DOT:55,
-  ecodes.KEY_SLASH:56, ecodes.KEY_RIGHT:79, ecodes.KEY_LEFT:80,
-  ecodes.KEY_DOWN:81,  ecodes.KEY_UP:82
-}.items(): HID.setdefault(ev, h)
-
-MOD = { ecodes.KEY_LEFTCTRL:1, ecodes.KEY_LEFTSHIFT:2, ecodes.KEY_LEFTALT:4,
-        ecodes.KEY_LEFTMETA:8, ecodes.KEY_RIGHTCTRL:16, ecodes.KEY_RIGHTSHIFT:32,
-        ecodes.KEY_RIGHTALT:64, ecodes.KEY_RIGHTMETA:128 }
-
-try:
-    dev = InputDevice(DEV)
-except FileNotFoundError:
-    sys.exit(f"Input device {DEV} not found")
-
-dev.grab()
-sock = socket.create_connection((IP,PORT), timeout=5)
-sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
-
-mods, keys = 0, []
-
-def send():
-    sock.sendall(bytes([mods,0]+keys[:6]+[0]*(6-len(keys))))
-
-def quit_handler(sig, frame):     # graceful Ctrl-C
-    dev.ungrab(); sock.close(); sys.exit(0)
-
-signal.signal(signal.SIGINT, quit_handler)
-
-for ev in dev.read_loop():
-    if ev.type != ecodes.EV_KEY: continue
-    pressed = ev.value == 1
-    if ev.code in MOD:
-        mods = mods | MOD[ev.code] if pressed else mods & ~MOD[ev.code]
-    elif ev.code in HID:
-        h = HID[ev.code]
-        if pressed and h not in keys: keys.insert(0,h)
-        elif not pressed and h in keys: keys.remove(h)
-    else:
-        continue
-    send()
-PYCODE
-
diff --git a/scripts/install-client.sh b/scripts/install-client.sh
new file mode 100755
index 0000000..1502b10
--- /dev/null
+++ b/scripts/install-client.sh
@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+sudo pacman --needed --noconfirm -S git rustup protobuf gcc evtest
+rustup toolchain install stable
+
+WORK=$HOME/.local/src/navka
+if [ ! -d "$WORK" ]; then git clone ssh://git@scm.bstein.dev:2242/brad_stein/navka.git "$WORK"; fi
+cd "$WORK" && git pull
+
+cargo build --release --manifest-path client/Cargo.toml
+install -Dm755 target/release/navka-client ~/.local/bin/navka-client
+
+mkdir -p ~/.config/systemd/user
+cat <<'EOF' > ~/.config/systemd/user/navka-client.service
+[Unit]
+After=network.target
+[Service]
+ExecStart=%h/.local/bin/navka-client
+Restart=on-failure
+[Install]
+WantedBy=default.target
+EOF
+
+systemctl --user daemon-reload
+systemctl --user enable --now navka-client.service
+echo "navka-client installed."
diff --git a/scripts/install-server.sh b/scripts/install-server.sh
new file mode 100755
index 0000000..6906380
--- /dev/null
+++ b/scripts/install-server.sh
@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+sudo pacman --needed --noconfirm -S git rustup protobuf gcc
+rustup toolchain install stable
+
+WORK=/opt/navka
+if [ ! -d "$WORK" ]; then sudo git clone ssh://git@scm.bstein.dev:2242/brad_stein/navka.git "$WORK"; fi
+cd "$WORK" && sudo git pull
+
+cargo build --release --manifest-path server/Cargo.toml
+sudo install -Dm755 target/release/navka-server /usr/local/bin/navka-server
+sudo install -Dm755 gadget/navka-gadget.sh   /usr/local/bin/navka-gadget.sh
+
+cat <<'EOF' | sudo tee /etc/systemd/system/navka-server.service
+[Unit]
+After=network.target navka-gadget.service
+[Service]
+ExecStart=/usr/local/bin/navka-server
+Restart=always
+User=root
+[Install]
+WantedBy=multi-user.target
+EOF
+
+cat <<'EOF' | sudo tee /etc/systemd/system/navka-gadget.service
+[Unit]
+Description=USB Gadget
+[Service]
+Type=oneshot
+ExecStart=/usr/local/bin/navka-gadget.sh
+RemainAfterExit=yes
+[Install]
+WantedBy=multi-user.target
+EOF
+
+sudo systemctl daemon-reload
+sudo systemctl enable --now navka-gadget.service navka-server.service
+echo "navka-server installed."
diff --git a/server/Cargo.toml b/server/Cargo.toml
new file mode 100644
index 0000000..b5e2907
--- /dev/null
+++ b/server/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "navka-server"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio         = { version = "1", features = ["rt-multi-thread", "macros"] }
+navka-common  = { path = "../common" }
+tokio-stream  = "0.1"
diff --git a/server/src/main.rs b/server/src/main.rs
new file mode 100644
index 0000000..831c715
--- /dev/null
+++ b/server/src/main.rs
@@ -0,0 +1,43 @@
+use navka_common::navka::{relay_server::{Relay, RelayServer}, HidReport};
+use tokio::{fs::OpenOptions, io::AsyncWriteExt, sync::mpsc};
+use tokio_stream::wrappers::ReceiverStream;
+use tonic::{transport::Server, Request, Response, Status};
+
+const HID_DEV: &str = "/dev/hidg0";
+
+#[derive(Default)]
+struct RelaySvc;
+
+#[tonic::async_trait]
+impl Relay for RelaySvc {
+    type StreamStream = ReceiverStream<Result<HidReport, Status>>;
+
+    async fn stream(
+        &self,
+        request: Request<tonic::Streaming<HidReport>>,
+    ) -> Result<Response<Self::StreamStream>, Status> {
+        let mut inbound = request.into_inner();
+        let (tx, rx) = mpsc::channel(8);
+
+        // writer task: client → hidg0
+        tokio::spawn(async move {
+            let mut hid = OpenOptions::new().write(true).open(HID_DEV).await.unwrap();
+            while let Some(Ok(report)) = inbound.message().await {
+                hid.write_all(&report.data).await.unwrap();
+            }
+        });
+
+        // nothing to send back yet
+        Ok(Response::new(ReceiverStream::new(rx)))
+    }
+}
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let addr = "0.0.0.0:4000".parse()?;
+    Server::builder()
+        .add_service(RelayServer::new(RelaySvc::default()))
+        .serve(addr)
+        .await?;
+    Ok(())
+}
diff --git a/server/tests/hid.rs b/server/tests/hid.rs
new file mode 100644
index 0000000..a9361fe
--- /dev/null
+++ b/server/tests/hid.rs
@@ -0,0 +1,14 @@
+#[tokio::test]
+async fn hid_roundtrip() {
+    use navka_common::navka::*;
+    use navka_server::RelaySvc;           // export the struct in lib.rs
+    let svc = RelaySvc::default();
+    let (mut cli, srv) = tonic::transport::Channel::balance_channel(1);
+    tokio::spawn(tonic::transport::server::Server::builder()
+        .add_service(relay_server::RelayServer::new(svc))
+        .serve_with_incoming(srv));
+
+    let (mut tx, mut rx) = relay_client::RelayClient::new(cli).stream().await.unwrap().into_inner();
+    tx.send(HidReport { data: vec![0,0,4,0,0,0,0,0] }).await.unwrap();
+    assert!(rx.message().await.unwrap().is_none());   // nothing echoed yet
+}