If you came across dev-widgets.cryptocompare.com and wondered whether it's safe to use, the short answer is that there's not much to evaluate: the page is essentially a blank error. The domain belongs to the well-known crypto data site CryptoCompare, but this subdomain appears to be either a broken development endpoint or an abandoned project.
For a crypto-related site, even a developer tools subdomain, you'd expect basic accountability: a way to contact the team, an about page, or at least a working service. Here, none of that exists. The site has no privacy policy, no terms of service, and no social media presence. Combined with a 404 status, it's hard to see this as anything other than an inactive or experimental page.
If you're looking for CryptoCompare widgets or developer resources, stick to the main site. This subdomain doesn't provide any functional tool or information, and there's no evidence it ever did. The absence of any web archive history suggests it's very new or never really launched. For a crypto-related property, that's a warning sign, not a neutral detail. Until there's a real site with clear ownership and content, consider dev-widgets.cryptocompare.com untrustworthy.