With 16,100 GitHub stars and created by Solomon Hykes (co-founder of Docker), Dagger eliminates proprietary YAML DSLs from CI/CD by letting developers write pipelines as real programs in their preferred language — then executing them identically on a laptop, in GitHub Actions, in GitLab CI, or on any machine with a container runtime. The BuildKit-based Dagger Engine runs every pipeline operation inside OCI containers, constructing a directed acyclic graph where each node is cached by default, parallelized automatically, and produces bit-for-bit reproducible outputs regardless of execution environment. Native SDKs generated from the GraphQL API schema provide Go, Python, TypeScript, PHP, Java, .NET, Elixir, and Rust developers with full type safety, IDE autocomplete, and the ability to unit-test CI pipelines using the same testing frameworks as application code. The module ecosystem enables cross-language composition where a Python team can invoke a Go team's build functions without learning Go, while filesystems, secrets, git repositories, and network tunnels are passed between functions as strongly-typed objects. Pipeline operations cache at container-layer granularity with content-addressed deduplication, and the interactive REPL enables step-by-step pipeline debugging with live container inspection. Host dependencies are explicit and strictly typed, eliminating implicit environment coupling that causes "works on my machine" failures. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.