ShadowAPI
ShadowAPI is a local contract-aware backend simulator that lets frontend and backend development run in parallel. It serves realistic mock APIs early in development and automatically routes requests to the real backend once available — without changing frontend code or URLs.
ShadowAPI is an open-source development gateway that removes backend dependency during early development.
Given an API contract, it instantly generates a realistic, stateful mock server so frontend teams can build and test without waiting for backend implementation.
As the real backend becomes available, ShadowAPI seamlessly forwards requests to the actual service while preserving the same endpoint URL. Missing or incomplete endpoints automatically fall back to mock responses, allowing gradual and predictable integration.
By acting as a contract-aware proxy between the frontend and backend, ShadowAPI enables true parallel development, prevents late integration failures, and eliminates reliance on cloud mock services or fragile hardcoded data. It is especially useful for student projects, hackathons, CI environments, and open-source contributors who need reproducible local setups.\