airbnb/viaduct

Viaduct is a GraphQL-based system that provides a unified interface for accessing and interacting with any data source.

Viaduct solves the problem of fragmented data access across multiple sources by presenting a single, integrated GraphQL schema that connects domains across an organization. Rather than treating GraphQL as a thin query layer over microservices, Viaduct functions as a serverless platform where teams host business logic directly. This approach enables logic to compose with other logic through GraphQL fragments and queries—a capability the project calls re-entrancy—which maintains modularity and prevents the hazards of traditional monolithic architectures.

Organizations should adopt Viaduct if they operate multiple data sources and teams across different domains that need to work with a unified schema. The tool suits companies willing to host business logic within the platform rather than maintaining separate microservices, and teams that value the ability for hosted logic to call other hosted logic through GraphQL. The project explicitly positions itself as counter to conventional GraphQL best practices, which typically advocate for thin GraphQL layers over external services.

The Viaduct engine runs in production at scale within Airbnb and has demonstrated reliability there, though the developer API remains under active development with parts subject to future change according to the project's roadmap. The project invites external developers to contribute and influence the direction of the API at this stage. The codebase is written in Kotlin and requires JDK 17 or later on macOS or Linux for building. Demonstration applications and a CLI starter are available separately to help new developers begin working with the system.