You don’t need one staging environment simulating the entire platform. You can have small staging environments that run some parts of the product, for example the latest version of the advertiser dashboard or the messaging inbox.
Sure, you won’t be simulating a whole class of problems that can arise at scale, but you can still test the more localized features in a safe environment.
Yes, I understand that. That's why it's unclear what it means that Twitter has "no test environment". That could mean a lot of things, some catastrophic and some not.
Sure, you won’t be simulating a whole class of problems that can arise at scale, but you can still test the more localized features in a safe environment.