Dockup is a preview environment and deployment platform that creates automatic preview deployments for every pull request or branch. It allows development teams to test and review changes in isolated staging environments before merging to production. Key features include: - Preview environments for pull requests - Automated deployment previews - Docker-based deployments - GitHub integration - Custom domains with free SSL - Managed databases Dockup is ideal for developers and teams looking for preview environments, deployment automation, and staging environments without complex DevOps setup. It is commonly used as an alternative to Vercel, Netlify, and Railway.