diff --git a/straxen/contexts.py b/straxen/contexts.py
index c027733e3..453de9ada 100644
--- a/straxen/contexts.py
+++ b/straxen/contexts.py
@@ -192,7 +192,8 @@ def xenonnt_online(output_folder='./strax_data',
             readonly=not we_are_the_daq,
             take_only=('veto_intervals',
                        'online_peak_monitor',
-                       'event_basics',))]
+                       'event_basics',
+                       'online_monitor_nv'))]
 
     # Remap the data if it is before channel swap (because of wrongly cabled
     # signal cable connectors) These are runs older than run 8797. Runs
diff --git a/straxen/plugins/online_monitor.py b/straxen/plugins/online_monitor.py
index dd1c640cc..b05168c5d 100644
--- a/straxen/plugins/online_monitor.py
+++ b/straxen/plugins/online_monitor.py
@@ -1,5 +1,6 @@
 import strax
 import numpy as np
+from immutabledict import immutabledict
 
 export, __all__ = strax.exporter()
 
@@ -175,3 +176,65 @@ def area_width_hist(self, data):
             range=self.config['area_vs_width_bounds'],
             bins=self.config['area_vs_width_nbins'])
         return hist.T
+
+
+@export
+@strax.takes_config(
+    strax.Option(
+        'channel_map', 
+        track=False, 
+        type=immutabledict,
+        help="immutabledict mapping subdetector to (min, max) \
+              channel number.")
+)
+class OnlineMonitorNV(strax.Plugin):
+    """
+    Plugin to write data of nVeto detector to the online-monitor. 
+    Data that is written by this plugin should be small (~MB/chunk) 
+    to not overload the runs-database.
+    
+    This plugin takes 'hitlets_nv' and 'events_nv'. Although they are
+    not strictly related, they are aggregated into a single data_type
+    in order to minimize the number of documents in the online monitor.
+    
+    Produces 'online_monitor_nv' with info on the hitlets_nv and events_nv
+    """
+
+    depends_on = ('hitlets_nv', 'events_nv')
+    provides = 'online_monitor_nv'
+    data_kind = 'online_monitor_nv'
+    __version__ = '0.0.2'
+    rechunk_on_save = False
+
+    def infer_dtype(self):
+        min_pmt, max_pmt = self.config['channel_map']['nveto']
+        n_pmt = (max_pmt - min_pmt) + 1
+        dtype = [
+            (('Start time of the chunk', 'time'),
+             np.int64),
+            (('End time of the chunk', 'endtime'),
+             np.int64),
+            (('hitlets_nv per channel', 'hitlets_nv_per_channel'),
+             (np.int64, n_pmt)),
+            (('events_nv per chunk', 'events_nv_per_chunk'),
+             np.int64)
+        ]
+        return dtype
+
+    def compute(self, hitlets_nv, events_nv, start, end):
+        # General setup
+        res = np.zeros(1, dtype=self.dtype)
+        res['time'] = start
+        res['endtime'] = end
+        min_pmt, max_pmt = self.config['channel_map']['nveto']
+        n_pmt = (max_pmt - min_pmt) + 1
+
+        # Count number of hitlets_nv per PMT
+        hitlets_channel_count, _ = np.histogram(hitlets_nv['channel'],
+                                                 bins=n_pmt,
+                                                 range=[min_pmt, max_pmt + 1])        
+        res['hitlets_nv_per_channel'] = hitlets_channel_count
+        
+        # Count number of events_nv per chunk
+        res['events_nv_per_chunk'] = len(events_nv)
+        return res