GraphQL Data Mocking at Scale with LLMs and @generateMock

Airbnb introduces @generateMock, a GraphQL client directive that uses LLMs to automatically generate realistic, type-safe mock data for testing and prototyping.

• •Engineers add @generateMock to any GraphQL operation, fragment, or field and run their existing Niobe code generator to produce JSON mock files and typed helper functions
• •The directive accepts optional arguments: id for naming, hints for custom instructions (e.g. "Include travel entries for Barcelona"), and designURL to match a Figma mockup
• •Context passed to the LLM includes the query definition, trimmed schema subset with inline docs, design snapshot image, platform target, and a curated list of valid Airbnb image URLs to prevent hallucinated URLs
• •Niobe is fine-tuned against Gemini 2.5 Pro for its 1M token context window and generation speed
• •The system preserves manual edits to generated JSON on subsequent regeneration runs