Suspicious seems inappropriately sinister. The project you linked is a go project, the OP is JavaScript. Imitation is the most sincere form of flattery.
It just outputs the mail it receives to stdout as JSON for easy parsing. Sending to specific email addresses "e.g. 451-please-try-again-later@smtperrors.com" will trigger specific SMTP errors.
Doesn't appear to support https. Ideally a similar mechanism to say Fiddler/Charles Proxy where a certificate is provided and appropriately translates the https between both sides of the connection. Obviously you would need to trust a new root. I'm fine with that on a dev/qe machine.
Basically, DNS injection for a machine would mean no noticeable difference in HTTPS.
Similar project: http://greim.github.io/hoxy/ - It also has throttling and latency simulation, but not as fine-grained. It's focus is more generally on debugging and traffic manipulation.
Would it be possible to sort traffic by L2 or L3, and only apply to certain MACs or IP addresses? I can see that being very useful for PXE and provisioning in "cloud" environments.
Please make airbnb run this. Their site is such utter cow dung on a flaky connection. It would cache broken assets, they must test with a 1G connection to the colo.
