diff --git a/scripts/sim_cameras.sh b/scripts/sim_cameras.sh
new file mode 100755
index 0000000..9653f1f
--- /dev/null
+++ b/scripts/sim_cameras.sh
@@ -0,0 +1,150 @@
+#!/usr/bin/env bash
+# Simulate RTSP cameras by looping mp4 files through MediaMTX + ffmpeg.
+#
+# Usage: ./scripts/sim_cameras.sh
+#
+# Reads camera ids from config/vigilar.toml, expects videos/<id>.mp4 for each,
+# starts MediaMTX on 127.0.0.1:8554, spawns one ffmpeg per camera, and writes
+# config/vigilar.sim.toml with rtsp_urls rewritten to the local endpoints.
+# Ctrl-C tears everything down.
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+REAL_CONFIG="${REPO_ROOT}/config/vigilar.toml"
+SIM_CONFIG="${REPO_ROOT}/config/vigilar.sim.toml"
+VIDEOS_DIR="${REPO_ROOT}/videos"
+SIM_DIR="${REPO_ROOT}/.sim"
+LOG_DIR="${SIM_DIR}/logs"
+MEDIAMTX_BIN="${SIM_DIR}/mediamtx"
+RTSP_HOST="127.0.0.1"
+RTSP_PORT="8554"
+
+MEDIAMTX_PID=""
+FFMPEG_PIDS=()
+
+cleanup() {
+  local pid
+  for pid in "${FFMPEG_PIDS[@]}"; do
+    if [[ -n "${pid}" ]] && kill -0 "${pid}" 2>/dev/null; then
+      kill "${pid}" 2>/dev/null || true
+    fi
+  done
+  if [[ -n "${MEDIAMTX_PID}" ]] && kill -0 "${MEDIAMTX_PID}" 2>/dev/null; then
+    kill "${MEDIAMTX_PID}" 2>/dev/null || true
+  fi
+  sleep 0.3
+  for pid in "${FFMPEG_PIDS[@]}" "${MEDIAMTX_PID}"; do
+    if [[ -n "${pid}" ]] && kill -0 "${pid}" 2>/dev/null; then
+      kill -9 "${pid}" 2>/dev/null || true
+    fi
+  done
+  rm -rf "${SIM_DIR:?}/logs"
+}
+trap cleanup EXIT INT TERM
+
+die() { echo "error: $*" >&2; exit 1; }
+
+# --- prereq checks ---------------------------------------------------------
+
+command -v ffmpeg >/dev/null 2>&1 || die "ffmpeg not found on PATH. Install it and retry."
+[[ -x "${MEDIAMTX_BIN}" ]] || die "MediaMTX binary not found at ${MEDIAMTX_BIN}. Run: scripts/download_mediamtx.sh"
+[[ -f "${REAL_CONFIG}" ]] || die "config file not found: ${REAL_CONFIG}"
+[[ -d "${VIDEOS_DIR}" ]] || die "videos directory not found: ${VIDEOS_DIR} (create it and drop <camera_id>.mp4 files inside)"
+
+# --- parse camera ids from vigilar.toml ------------------------------------
+# Grab every `id = "..."` line that sits inside a [[cameras]] block.
+
+mapfile -t CAMERA_IDS < <(awk '
+  /^\[\[cameras\]\]/ { in_cams = 1; next }
+  /^\[/ && !/^\[\[cameras\]\]/ { in_cams = 0 }
+  in_cams && /^[[:space:]]*id[[:space:]]*=/ {
+    match($0, /"([^"]+)"/, m)
+    if (m[1] != "") print m[1]
+  }
+' "${REAL_CONFIG}")
+
+[[ ${#CAMERA_IDS[@]} -gt 0 ]] || die "no [[cameras]] blocks with an id field found in ${REAL_CONFIG}"
+
+# --- verify every camera has a matching video -----------------------------
+
+MISSING=()
+for id in "${CAMERA_IDS[@]}"; do
+  [[ -f "${VIDEOS_DIR}/${id}.mp4" ]] || MISSING+=("${VIDEOS_DIR}/${id}.mp4")
+done
+if [[ ${#MISSING[@]} -gt 0 ]]; then
+  echo "error: missing video files for cameras:" >&2
+  for f in "${MISSING[@]}"; do echo "  - ${f}" >&2; done
+  exit 1
+fi
+
+# --- start MediaMTX --------------------------------------------------------
+
+mkdir -p "${LOG_DIR}"
+echo "Starting MediaMTX on ${RTSP_HOST}:${RTSP_PORT}..."
+"${MEDIAMTX_BIN}" >"${LOG_DIR}/mediamtx.log" 2>&1 &
+MEDIAMTX_PID=$!
+
+for _ in $(seq 1 30); do
+  if (exec 3<>"/dev/tcp/${RTSP_HOST}/${RTSP_PORT}") 2>/dev/null; then
+    exec 3<&- 3>&-
+    break
+  fi
+  sleep 0.1
+done
+if ! (exec 3<>"/dev/tcp/${RTSP_HOST}/${RTSP_PORT}") 2>/dev/null; then
+  echo "MediaMTX failed to bind ${RTSP_HOST}:${RTSP_PORT}. Log tail:" >&2
+  tail -n 20 "${LOG_DIR}/mediamtx.log" >&2 || true
+  exit 1
+fi
+exec 3<&- 3>&- 2>/dev/null || true
+
+# --- spawn one ffmpeg per camera -------------------------------------------
+
+for id in "${CAMERA_IDS[@]}"; do
+  video="${VIDEOS_DIR}/${id}.mp4"
+  url="rtsp://${RTSP_HOST}:${RTSP_PORT}/${id}"
+  echo "Publishing ${video} -> ${url}"
+  ffmpeg -nostdin -loglevel warning \
+    -stream_loop -1 -re -i "${video}" \
+    -c copy -f rtsp "${url}" \
+    >"${LOG_DIR}/${id}.log" 2>&1 &
+  FFMPEG_PIDS+=($!)
+done
+
+# --- write the sim config --------------------------------------------------
+# Copy vigilar.toml, rewrite each `rtsp_url = "..."` line inside a
+# [[cameras]] block to point at the local MediaMTX endpoint for that camera.
+# Relies on `id` preceding `rtsp_url` within each block (the standing
+# convention in config/vigilar.toml).
+
+awk -v host="${RTSP_HOST}" -v port="${RTSP_PORT}" '
+  /^\[\[cameras\]\]/ { in_cams = 1; current_id = ""; print; next }
+  /^\[/ && !/^\[\[cameras\]\]/ { in_cams = 0; print; next }
+  in_cams && /^[[:space:]]*id[[:space:]]*=/ {
+    match($0, /"([^"]+)"/, m)
+    current_id = m[1]
+    print
+    next
+  }
+  in_cams && /^[[:space:]]*rtsp_url[[:space:]]*=/ && current_id != "" {
+    printf "rtsp_url = \"rtsp://%s:%s/%s\"\n", host, port, current_id
+    next
+  }
+  { print }
+' "${REAL_CONFIG}" > "${SIM_CONFIG}"
+
+# --- summary ---------------------------------------------------------------
+
+echo
+echo "Simulator running. ${#CAMERA_IDS[@]} stream(s):"
+for id in "${CAMERA_IDS[@]}"; do
+  echo "  rtsp://${RTSP_HOST}:${RTSP_PORT}/${id}"
+done
+echo
+echo "Sim config written to: ${SIM_CONFIG}"
+echo "Start Vigilar in another terminal:"
+echo "  vigilar start --config ${SIM_CONFIG#"${REPO_ROOT}"/}"
+echo
+echo "Press Ctrl-C to stop."
+
+wait