how can a website be tested in multiple resolutions (especially higher resolutions)?

My project's website doesn't look good on higher resolutions (especially, the body text looks too small) as reported by a friend. Are there any tools or methods to test websites on high-resolution screens?

I'm currently working on an MBP, so the site looks pretty balanced/proportionate on MBP and I was also able to make it look decent on mobile devices.

Here you go:…

Or use BrowserStack if you need actual devices.

Thank you @pugson, I actually do test mobile viewports using chrome and I made improvements there. I just realized that I can add custom resolutions to test, thanks to your link! 🎉