CircleCI configuration syntax is structured YAML and starts with the version, a named job, and an executor type for that job, either docker, machine, or macos. CircleCI provides prebuilt Docker images for your convenience as described in the following video.

Secrets, Private Keys, Tokens, and Scripts

Encrypt and store secrets and private keys for your project by following the environment variables or contexts documentation. Review the best practices for using shell scripts to secure scripts and properly manage API tokens in your configuration.

Advanced Test Configuration

CircleCI enables you to parallelize your test runs for greatest efficiency. It is also possible to test with browsers and databases, refer to the Browser Testing and Database Configuration documents for details.