Force HTML -page reload from server application

I have python based CGI application on my server. It reads json file and generates an HTML page for the browser. But if json file is updated the HTML page should be reloaded.

Can any external code on the server somehow force HTML page reload? So that is open in the user’s browser.

Any ideas on how to solve this? It feels stupid code like “reload this HTML every X seconds”. What other opportunities do I have?