Epic Games open-sources Lore, a binary-first VCS

Epic Games has released Lore, a new open-source version control system (VCS) designed to treat binary files as first-class citizens alongside text-based code. The tool, originally developed as Unreal Revision Control for internal use and integrated into Unreal Editor for Fortnite, is now available under the MIT License, allowing broad adoption without copyleft restrictions.

Lore is positioned as a centralized, content-addressed VCS that prioritizes flexibility and performance for projects involving large binary assets. Unlike traditional VCS tools, which often relegate binaries to secondary status, Lore processes all content—whether text or binary—as opaque byte streams. Text-aware features are layered on top of this foundation, ensuring binaries receive equal treatment in storage and transport paths. The system is cross-platform, supporting macOS, Windows, and Linux, with a server-side architecture designed for deployment across cloud environments.

What Lore offers

Epic Games identifies several gaps in existing VCS tools that Lore aims to address. Git, while strong in revision graphing, treats binaries as "second-class citizens" and lacks multi-tenant isolation, a feature critical for shared infrastructure. Perforce, another industry standard, requires multiple server round trips for routine operations, which Epic describes as a performance bottleneck. Mercurial and its successor, Sapling, excel in scaling source repositories through distributed architecture but still prioritize text over binaries.

Lore’s design goals include a binary-first approach, sparse-by-construction architecture to minimize client-server round trips, and the elimination of partially applied revisions. The system also provides a full-surface API to support integration with various programming languages. Pre-built binaries and a quickstart guide are available on GitHub, despite the irony of hosting a VCS on a competing platform.

Target use cases

Epic’s primary audience for Lore is game developers, given the tool’s origins in Unreal Engine and Fortnite development. However, the system is also pitched for broader applications, including AI model development, systems engineering, and any workflow involving large binary datasets alongside code. The MIT License’s permissiveness allows for proprietary forks, which could appeal to enterprises seeking customization without licensing constraints.

The release reflects Epic’s long-standing practice of open-sourcing internal tools, following precedents like Unreal Engine and the MetaHuman Creator. While Lore is not positioned as a replacement for Git or Perforce, it offers an alternative for teams struggling with binary-heavy workflows.

What to watch

Adoption of Lore will likely hinge on its performance in real-world scenarios, particularly in industries where binary files dominate. Game studios, AI research teams, and systems developers may evaluate the tool as a potential complement or alternative to existing VCS solutions. The MIT License’s flexibility could also encourage third-party integrations, such as plugins for popular IDEs or cloud-based development environments. For now, Epic has provided the foundational components, leaving the broader developer community to determine Lore’s place in the version control ecosystem.