diff --git a/dev-sx-native.sh b/dev-sx-native.sh
new file mode 100755
index 00000000..bb47dc38
--- /dev/null
+++ b/dev-sx-native.sh
@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Dev mode for sx_docs using the native OCaml HTTP server.
+# No Docker, no Python, no Quart — just the OCaml binary.
+# Caddy still handles TLS and static files on externalnet.
+#
+# Usage:
+#   ./dev-sx-native.sh              # Start on port 8013
+#   ./dev-sx-native.sh 8014         # Start on custom port
+#   ./dev-sx-native.sh --build      # Rebuild OCaml binary first
+
+PORT="${1:-8013}"
+BUILD=false
+
+if [[ "${1:-}" == "--build" ]]; then
+  BUILD=true
+  PORT="${2:-8013}"
+fi
+
+# Build if requested or binary doesn't exist
+BIN="hosts/ocaml/_build/default/bin/sx_server.exe"
+if [[ "$BUILD" == true ]] || [[ ! -f "$BIN" ]]; then
+  echo "[dev-sx-native] Building OCaml binary..."
+  cd hosts/ocaml && eval "$(opam env)" && dune build bin/sx_server.exe && cd ../..
+  echo "[dev-sx-native] Build complete"
+fi
+
+# Set project dir so the server finds spec/, lib/, web/, sx/sx/
+export SX_PROJECT_DIR="$(pwd)"
+
+echo "[dev-sx-native] Starting OCaml HTTP server on port $PORT"
+echo "[dev-sx-native] project=$SX_PROJECT_DIR"
+echo "[dev-sx-native] binary=$BIN"
+echo ""
+
+exec "$BIN" --http "$PORT"