Irmin

Irmin is a distributed, versioned store library for the OCaml programming language. It provides a Git-like experience for application data, allowing developers to create branches, commit changes, merge divergent histories, and synchronize state across multiple environments.

At its core, Irmin uses functional, immutable data structures and a content-addressable store. Data is organized as trees that map paths to contents, and changes are recorded as commits linked into a Merkle DAG. This design supports offline work, reproducible snapshots, and deterministic merging strategies.

Irmin offers a generic store interface with pluggable backends. In practice, applications may run with an in-memory backend for testing or a Git-backed backend that stores data in a Git repository; the architecture is extensible to other storage systems and custom backends. The library also provides facilities for transactional updates and for defining custom merge policies for conflict resolution.

Irmin is primarily used in the OCaml ecosystem, including MirageOS-based projects, to manage configuration, state, or data that needs to be versioned and synchronized. It is an open-source project developed by contributors in the OCaml community and supported by its modular, composable API.