Act vs diff-so-fancy

act is an open-source command-line tool that runs GitHub Actions workflows locally using Docker containers. It reads workflow files from .github/workflows/ and executes them with environment variables and filesystem configurations matching GitHub's hosted runners. The tool enables fast local feedback on workflow changes without requiring commits and pushes to a remote repository.

diff-so-fancy Git diff output enhancer that makes diffs more human-readable with better highlighting and formatting.