When you land on assets.app.plangrid.com, you're met with a 404 error — the page doesn't exist. That's the first and loudest signal about this subdomain. For a legitimate asset server or backend service, a working page (or at least a redirect) is standard. This one is essentially a dead link.
There's no record of this site in the Wayback Machine, no contact info, no about page, and no social media presence. The WHOIS data for the parent domain plangrid.com is not publicly available here, so confirming the current ownership is difficult. While the subdomain could be an abandoned project of a known company, the lack of any functioning content makes it impossible to verify that.
If you're looking for assets.app.plangrid.com reviews, there are none — the site has no history. The question 'is assets.app.plangrid.com a scam' is hard to answer because there's nothing to evaluate. It's not actively malicious, but it's also not trustworthy for any purpose. Without a real page, there's no service to use, no information to rely on, and no reason to engage.