The term "reproducible build" refers to a build process that produces identical results on every run, allowing for reliable connection between source code and build artifacts, verification of build outputs, and improved software supply chain security. Creating reproducible builds is challenging due to the large number of variables involved in the usual build process, including host operating system, timezone, environment configuration, compiler, and file timestamps. Dagger, a tool that executes pipelines entirely as standard OCI containers, aims to make reproducible builds easier to implement by isolating the build environment from the host filesystem and environment, reducing build variance, and providing mechanisms to audit the build environment. Additionally, Dagger addresses part of the biggest source of reproducibility issues related to file timestamps, allowing for deterministic build paths and eliminating variation in the build process. The future development of Dagger may include support for the SOURCE_DATE_EPOCH variable, disabling internet access during container execution, verifying files via checksums, fine-grained source policies, and tools that identify non-deterministic aspects of builds.