lore

Lore is an open-source version control system developed by Epic Games, built with Rust and released under the MIT license. It is designed for projects that combine source code with large binary assets, such as games and entertainment productions, and aims to scale for both data volume and team size. The system is centralized and content-addressed, representing repository state as Merkle trees backed by an immutable revision chain. Files are stored as reusable chunks with indexed lookup, enabling deduplication and efficient transfer of large binary assets. Workspaces support on-demand hydration and sparse checkout, fetching file data only when needed rather than downloading everything upfront. Key characteristics include lightweight branches that can be created and switched without duplicating underlying data, a tamper-evident revision history derived from cryptographic hashes, and a service-backed architecture with caching in front of durable storage to scale throughput for large teams. Lore provides a CLI for full access to its functionality, and offers SDK bindings for C/C++, C#, Rust, Go, Python, and JavaScript for integration and extension. It is also the built-in version control system for UEFN (Unreal Editor for Fortnite), though the open source release currently cannot interoperate with UEFN builds due to a proprietary compression format; the project is actively working to close that gap. The project is pre-1.0 and under active development, with interfaces, on-disk formats, and APIs subject to change between releases. The roadmap includes features such as scalable locking and an open source desktop client. Installation is available via shell scripts for macOS/Linux and PowerShell for Windows, with a demo mode for local server evaluation.