Confirming it worked.
WHY VERIFY
A deployment that completes is not necessarily a deployment that worked.
WHAT TO CHECK IMMEDIATELY
The site responds The log is clean The deployed version is what you expected
WHAT TO TEST
The most important paths, not only the homepage.
WHAT TO INCLUDE IN THAT LIST
Sign-in The main task users perform Anything involving payment Form submission
WHAT ELSE TO CONFIRM
Scheduled tasks still run Background workers are running the new code Mail still sends Static assets load
WHAT TO WATCH FOR THE FOLLOWING HOUR
Error rates Response times Support requests
WHY THAT WINDOW
Problems frequently appear only under real traffic.
WHAT TO AUTOMATE
A set of checks run after every deployment.
WHAT THEY SHOULD DO
Fail loudly if something is wrong.
WHAT TO DO IF SOMETHING IS WRONG
Revert first, investigate afterwards.
WHAT TO RECORD
The deployment, and whether verification passed.