diff --git a/Dockerfile b/Dockerfile
index 4a9667b..5c7ebd2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,6 +11,7 @@ RUN pip install --no-cache-dir \
     python-multipart==0.0.20
 
 COPY app/ ./app/
+COPY scripts/ ./scripts/
 
 ENV COSMA_QC_DB=/var/lib/cosma-qc/jobs.db
 
diff --git a/app/main.py b/app/main.py
index a357bc6..de412b6 100644
--- a/app/main.py
+++ b/app/main.py
@@ -310,3 +310,81 @@ async def retry_stitch(stitch_id: int):
             (stitch_id,),
         )
     return {"ok": True}
+
+
+VIEWER_PORT_BASE = 8200
+VIEWER_SCRIPT_REMOTE = "/tmp/cosma-viser_ply.py"
+
+
+def _worker_by_host(host: str) -> dict | None:
+    for w in WORKERS:
+        if w["host"] == host:
+            return w
+    return WORKERS[0] if WORKERS else None
+
+
+async def _launch_viewer(worker: dict, ply_path: str, port: int) -> None:
+    alias = worker["ssh_alias"]
+    local_script = Path(__file__).parent.parent / "scripts" / "viser_ply.py"
+    proc = await asyncio.create_subprocess_exec(
+        "scp", "-o", "BatchMode=yes", str(local_script), f"{alias}:{VIEWER_SCRIPT_REMOTE}",
+        stdout=asyncio.subprocess.DEVNULL, stderr=asyncio.subprocess.PIPE,
+    )
+    _, err = await proc.communicate()
+    if proc.returncode != 0:
+        raise HTTPException(500, f"scp viser_ply.py failed: {err.decode()[:200]}")
+    wrapper = (
+        f"#!/bin/bash\n"
+        f"pkill -f 'viser_ply.py.*--port {port}' 2>/dev/null\n"
+        f"sleep 1\n"
+        f"cd /home/floppyrj45/ai-video/lingbot-map\n"
+        f"source .venv/bin/activate\n"
+        f"exec python3 {VIEWER_SCRIPT_REMOTE} {ply_path!r} --port {port} --downsample 0\n"
+    )
+    wrapper_path = f"/tmp/cosma-viser-launch-{port}.sh"
+    proc = await asyncio.create_subprocess_exec(
+        "ssh", "-o", "BatchMode=yes", alias,
+        f"cat > {wrapper_path} && chmod +x {wrapper_path}",
+        stdin=asyncio.subprocess.PIPE,
+        stdout=asyncio.subprocess.DEVNULL, stderr=asyncio.subprocess.PIPE,
+    )
+    _, err = await proc.communicate(wrapper.encode())
+    if proc.returncode != 0:
+        raise HTTPException(500, f"wrapper write failed: {err.decode()[:200]}")
+    proc = await asyncio.create_subprocess_exec(
+        "ssh", "-o", "BatchMode=yes", alias,
+        f"setsid nohup {wrapper_path} </dev/null >/tmp/cosma-viser-{port}.log 2>&1 & disown; sleep 0.3",
+        stdout=asyncio.subprocess.DEVNULL, stderr=asyncio.subprocess.PIPE,
+    )
+    await proc.communicate()
+    await asyncio.sleep(5)
+
+
+@app.post("/jobs/{job_id}/view")
+async def view_job(job_id: int):
+    with closing(db()) as conn:
+        row = conn.execute(
+            "SELECT ply_path, worker_host FROM jobs WHERE id=? AND status='done'",
+            (job_id,),
+        ).fetchone()
+    if not row or not row["ply_path"]:
+        raise HTTPException(404, "PLY non disponible")
+    worker = _worker_by_host(row["worker_host"]) or WORKERS[0]
+    port = VIEWER_PORT_BASE + job_id
+    await _launch_viewer(worker, row["ply_path"], port)
+    return {"url": f"http://{worker['host']}:{port}"}
+
+
+@app.post("/stitches/{stitch_id}/view")
+async def view_stitch(stitch_id: int):
+    with closing(db()) as conn:
+        row = conn.execute(
+            "SELECT output_ply, worker_host FROM stitches WHERE id=? AND status='done'",
+            (stitch_id,),
+        ).fetchone()
+    if not row or not row["output_ply"]:
+        raise HTTPException(404, "PLY stitch non disponible")
+    worker = _worker_by_host(row["worker_host"]) or WORKERS[0]
+    port = VIEWER_PORT_BASE + 1000 + stitch_id
+    await _launch_viewer(worker, row["output_ply"], port)
+    return {"url": f"http://{worker['host']}:{port}"}
diff --git a/app/static/style.css b/app/static/style.css
index d58b6f1..8f02c34 100644
--- a/app/static/style.css
+++ b/app/static/style.css
@@ -74,6 +74,11 @@ progress::-moz-progress-bar { background: var(--accent); }
   white-space: nowrap; }
 .job-list .dur { color: var(--muted); font-size: 0.78rem; }
 .job-list .ext { margin-left: 0.5rem; color: var(--accent); font-size: 0.75rem; }
+button.ext.viewer-btn { background: transparent; border: 1px solid var(--accent);
+  color: var(--accent); font-size: 0.72rem; padding: 1px 6px; border-radius: 3px;
+  cursor: pointer; font-family: inherit; }
+button.ext.viewer-btn:hover { background: var(--accent); color: #000; }
+button.ext.viewer-btn:disabled { opacity: 0.6; cursor: wait; }
 
 .err-line { color: var(--err); font-size: 0.75rem;
   padding-left: 28px; padding-bottom: 0.25rem; }
diff --git a/app/templates/_jobs_table.html b/app/templates/_jobs_table.html
index 0bbcbf9..2525ce5 100644
--- a/app/templates/_jobs_table.html
+++ b/app/templates/_jobs_table.html
@@ -19,8 +19,8 @@
           </span>
           <span class="label">
             {{ j.auv }}/{{ j.gopro_serial }}/{{ j.segment_label }}
-            {% if j.status == 'done' and j.viser_url %}
-              <a class="ext" href="{{ j.viser_url }}" target="_blank">viser</a>
+            {% if j.status == 'done' and j.ply_path %}
+              <button class="ext viewer-btn" data-view-url="jobs/{{ j.id }}/view">viser</button>
             {% endif %}
           </span>
           <span class="dur">{{ j._duration }}</span>
@@ -56,7 +56,7 @@
                 {% else %}merge final{% endif %}
                 {% if s._duration %}<span class="dur muted"> — {{ s._duration }}</span>{% endif %}
                 {% if s.status == 'done' and s.output_ply %}
-                  <span class="ext" title="{{ s.output_ply }}">PLY</span>
+                  <button class="ext viewer-btn" data-view-url="stitches/{{ s.id }}/view" title="{{ s.output_ply }}">viser</button>
                 {% endif %}
               </span>
               {% if s.status in ('queued','running') %}
diff --git a/app/templates/index.html b/app/templates/index.html
index aab473e..4b92445 100644
--- a/app/templates/index.html
+++ b/app/templates/index.html
@@ -24,5 +24,24 @@
     <p class="muted">Chargement…</p>
   </div>
 </section>
+
+<script>
+document.addEventListener('click', async (e) => {
+  const btn = e.target.closest('.viewer-btn');
+  if (!btn) return;
+  e.preventDefault();
+  const url = btn.dataset.viewUrl;
+  btn.textContent = '…';
+  btn.disabled = true;
+  try {
+    const res = await fetch(url, { method: 'POST' });
+    const data = await res.json();
+    if (res.ok && data.url) window.open(data.url, '_blank');
+    else alert(data.detail || 'Erreur lancement viewer');
+  } catch (err) { alert('Erreur réseau: ' + err); }
+  btn.textContent = 'viser';
+  btn.disabled = false;
+});
+</script>
 </body>
 </html>
diff --git a/scripts/viser_ply.py b/scripts/viser_ply.py
new file mode 100644
index 0000000..05c810d
--- /dev/null
+++ b/scripts/viser_ply.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+"""Minimal standalone viser viewer for a single PLY point cloud.
+
+Usage:
+    python3 viser_ply.py path/to/cloud.ply --port 8200
+"""
+from __future__ import annotations
+
+import argparse
+import sys
+import time
+
+import numpy as np
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("ply", help="PLY file to visualize")
+    ap.add_argument("--port", type=int, default=8200)
+    ap.add_argument("--point-size", type=float, default=0.01)
+    ap.add_argument("--downsample", type=float, default=0.0,
+                    help="Voxel downsample size (0 = no downsample)")
+    ap.add_argument("--max-points", type=int, default=2_000_000,
+                    help="Random subsample to this many points if cloud is larger")
+    args = ap.parse_args()
+
+    try:
+        import open3d as o3d
+        import viser
+    except ImportError as e:
+        sys.exit(f"missing dep: {e}")
+
+    pcd = o3d.io.read_point_cloud(args.ply)
+    if args.downsample > 0:
+        pcd = pcd.voxel_down_sample(args.downsample)
+    pts = np.asarray(pcd.points, dtype=np.float32)
+    cols = np.asarray(pcd.colors, dtype=np.float32) if pcd.has_colors() else np.ones_like(pts) * 0.7
+    if len(pts) > args.max_points:
+        idx = np.random.choice(len(pts), args.max_points, replace=False)
+        pts, cols = pts[idx], cols[idx]
+    print(f"loaded {len(pts):,} pts from {args.ply}", flush=True)
+
+    server = viser.ViserServer(host="0.0.0.0", port=args.port)
+    server.scene.add_point_cloud(
+        "/cloud", points=pts, colors=(cols * 255).astype(np.uint8), point_size=args.point_size
+    )
+    print(f"viser listening on *:{args.port}")
+    while True:
+        time.sleep(60)
+
+
+if __name__ == "__main__":
+    main()