If Novu's Inbox renders but realtime notifications never arrive, you are probably missing socketUrl. The component does not infer the websocket endpoint from the backend URL, and EU apps must use the eu.ws.novu.co and eu.api.novu.co hosts explicitly. Pass socketUrl, backendUrl, applicationIdentifier, and subscriberId together, and check that the region in both URLs matches your Novu account region.

Context: Stack Overflow #79514587 (accepted self-answer): A developer wired up Novu's Inbox component following the docs but never received realtime in-app notifications without a refresh. The accepted fix was to pass socketUrl to the Inbox component explicitly, pointing it at the region's websocket endpoint (https://eu.ws.novu.co for EU, with backendUrl https://eu.api.novu.co), alongside the application identifier and subscriber id.