User Engagement Dashboard Build

I need a clean, responsive dashboard that lets me see how visitors actually interact with my site. The entire focus is data-driven visualization of user engagement, so I’m not looking to track sales or manage accounts—only to surface engagement insights in a way that’s quick to grasp and easy to act on.

Here’s what I’m after:

• Key engagement metrics visualised in real time (think session length, pages per session, click-through patterns, returning vs new users, scroll depth—whatever you recommend that best captures engagement).
• Interactive charts and graphs (line, bar, heat-map, cohort, etc.) built with a modern JS library such as Chart.js, D3.js, Highcharts or a framework you’re comfortable with.
• Ability to filter by date range, device type and referral source right from the dashboard.
• A lightweight back-end hookup so the dashboard pulls fresh data automatically from my existing analytics stack (Google Analytics 4 is in place; I can expose an API or give you access to BigQuery if that’s simpler).
• Mobile-first, responsive layout that can drop straight into a React component on my current site.
• Clear, maintainable code plus a short README so I can re-deploy or extend the visuals later.

Acceptance criteria
1. All chosen engagement metrics load under three seconds on a typical broadband connection.
2. Visual elements resize gracefully on screens from 320 px to 1920 px.
3. Filters update the visuals without a full-page reload.
4. No console errors or linting warnings in production mode.

Hand-over will include the full source, build scripts and a brief walkthrough video or live call—I’m flexible on that. If you’ve built similar dashboards before, please share a link or short description so I can see your approach.