Avoiding the Monolith Trap: Lessons from Airbnb’s Multi-Tenant GraphQL Platform

Session description

Over the past six years, Viaduct has grown from Airbnb’s unified data access layer into a central platform for hosting business logic — now supporting over 1 million lines of code, 500+ monthly contributors, and 100+ teams. That scale has brought a familiar risk: the slow creep toward monolith. Viaduct was never meant to be a microservices system, but we’ve had to make deliberate choices to preserve team autonomy, performance, and codebase sanity. This talk shares the strategies we’re using — and actively evolving — to make that possible, including: * Tenant modules that define slices of the GraphQL schema alongside their implementation logic; * Relying on GraphQL fragments instead of service calls for inter-module communication; * Building ownership and attribution into the platform so teams can trace metrics and errors back to themselves. We haven’t fully solved these challenges — but we’ve learned a lot about what works, what breaks, and what to watch for.