diff --git a/dap/zmqsocks.py b/dap/zmqsocks.py
index 55abf1e..c66d545 100644
--- a/dap/zmqsocks.py
+++ b/dap/zmqsocks.py
@@ -1,6 +1,8 @@
 import numpy as np
 import zmq
 
+from .utils import ExtendedJSONEncoder
+
 
 FLAGS = 0
 
@@ -61,10 +63,10 @@ class ZMQSocketsWorker:
 
 
     def send_accumulator(self, results):
-        self.accumulator_socket.send_json(results, FLAGS)
+        self.accumulator_socket.send_json(results, FLAGS, cls=ExtendedJSONEncoder)
 
     def send_visualisation(self, results, data):
-        self.visualisation_socket.send_json(results, FLAGS | zmq.SNDMORE)
+        self.visualisation_socket.send_json(results, FLAGS | zmq.SNDMORE, cls=ExtendedJSONEncoder)
         self.visualisation_socket.send(data, FLAGS, copy=True, track=True)