Hi @ocerafa did you take a look at clientside callbacks (https://dash.plot.ly/performance and 📣 Dash 0.41.0 released). Indeed, at the moment if your callback is written in Python I’m not sure it’s deserializing which takes most of the time. Indeed, the Python app running on the server first needs to retrieve the contents of the Div from the client, which would involve transferring the data over the network. You can probably eliminate this with a clientside callback written in Javascript (I’m a bit outside of my comfort zone here, I hope what I wrote is correct).