A beta version of Catsnap 3.0 is now available. 3.0 introduces a major architectural change: instead of accessing dynamodb directly, the command-line script is now a client to a postgres-backed web api. This has several advantages, including browser-based access, reduced operating costs (potentially all the way to $0.00), and improved security.
You'll need to run the server code somewhere. The instructions below assume you're using a VPS or EC2. However, you could also run catsnap on your personal computer, or a managed service like Heroku. In any case, you'll need to create a postgres database for Catsnap to use. First-time Catsnap users will also need to create an S3 bucket.