api.skype.com is a subdomain owned by Microsoft, the company behind Skype. That alone gives it strong legitimacy — the same company that runs one of the world's most popular communication platforms. But when you visit this subdomain, you get a 404 error. That means the page you're looking for doesn't exist, or the subdomain isn't meant for public browsing.
For an API endpoint, missing contact info, privacy policies, and social media links are completely normal. No one expects a developer-facing API to have an about page. The real question is whether the site is safe to interact with, and on that front there's nothing to worry about: the SSL certificate is valid, the connection is encrypted, and the server is hosted on Microsoft's own network. No blacklists or safety warnings came up.
If you came here expecting to find a working service, you probably need a different URL. The main Skype site at skype.com is where you want to go. As for "is api.skype.com a scam?" — no, it's just an inactive subdomain of a trusted company. Save your concern for sites that actually hide who runs them.