Act vs Changesets

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.

Changesets is an open-source tool for managing versioning and changelogs in JavaScript/TypeScript monorepos. It provides a workflow for contributors to declare version bumps and changelog entries that are applied during release.