When you land on r4.app.yellow.ai, you see what looks like a default OpenResty welcome page. That alone isn't damning, but for a site that appears to reference a commercial product line, the lack of transparency starts to stand out. There's no about page, no contact email, and the WHOIS record is hidden. Those are unusual for any business site, even a small one.
Most legitimate software companies put their team, their address, and at least a privacy policy somewhere. This site has none of that. The social media links point to OpenResty's official accounts, not to this subdomain, which raises the question of whether this site is even affiliated or just borrowing a name.
If you're wondering if r4.app.yellow.ai is a scam, the evidence is too thin to call it that, but the warnings are real. Without knowing who runs it or how to reach them, there's no reason to hand over any personal information or payment details. If you're here to download software or get support, use the official OpenResty domains instead. The lack of identity and contact info is a red flag you shouldn't ignore.