No, there is no domain whitelist or DNS restriction on the Hobby plan.

Railway allows full outbound HTTPS/HTTP requests on all plans (including Hobby). The selective DNS resolution errors you're seeing ([Errno -5] No address associated with hostname) are not caused by a whitelist.

Common Causes & Fixes:

1. Intermittent DNS Resolver Issues (Most Likely) Railway’s internal DNS sometimes flakes on certain domains, especially newer or less common ones (like Jupiter, Pyth, Together.xyz, etc.). Quick Fix:
   • Add these environment variables to your service: text

   NODE_OPTIONS=--dns-result-order=ipv4first  

   (If using Node.js)
   • Or force IPv4 in your code: JavaScript

   // Example with axios / fetch  
   const httpsAgent = new https.Agent({ family: 4 });  

2. Try Using Public IP Directly (Temporary Test) Resolve the failing domains manually and test with the raw IP.
3. Best Long-Term Solutions:
   • Upgrade to Pro plan → gets stable outbound networking + Static Egress IPs (recommended if you rely on many external APIs).
   • Route problematic requests through a proxy service like QuotaGuard, Bright Data, or a simple Cloudflare Worker.
4. Workaround Many People Use: Add a small delay + retry logic with exponential backoff when you get DNS errors.

Railway Team — this selective DNS failure on Hobby has been reported multiple times recently. Any known issue with the resolver for domains like *.jup.ag, hermes.pyth.network, api.together.xyz?

Paste the exact code you're using to make the requests (axios, fetch, etc.) and I can give you a more targeted fix.