On the web frontend, we paginate the reports and so it is supposed to be responsive with large datasets. We tested this with around 10K rows, we'll surely scale-up our tests for this.

BTW which charting library are you using for your reports?

On the few places in the frontend where charts are use I am using chart.js, which I'm happy with so far.

Most of the recurring reports simply spits out excel or csv files with no graphs.

I'm also doing something similar and using c3.js for charts.

Can you post your project?

You mean the source? I am not in a position to post the source, it's a product I'm developing with one client (who has it running) and another prospective client.

We haven't had time to make a marketing/demo site for it yet, sales has been through networking so far.