It really is amazing how many web services are dependent on S3. For instance, the Heroku dashboard is currently down for me. Along with all of my services that are on Heroku.
Same here, but worse. Some of the apps I have hosted on Heroku (including APIs) are showing "Application Error". Like you, tried logging into dashboard and got a Heroku error page.
I'll bet that what Heroku does is precompile all the code when you push to Heroku (or doesn't), saves it to a S3 bucket, and kills the running process after a certain amount of inactivity. Once it detects a pending network request, the code gets loaded from the S3 bucket into the EC2 instance, and then your code spins up.
