The internet was designed for human actors. Its discovery infrastructure — search engines, directories, and hyperlinked documents — assumes a human reading and navigating. Autonomous agents (bots) operating on the internet today face a structural gap: there is no machine-native, globally accessible index of services they can consume. This document defines the core infrastructure of the *API Index (APIX)*: a HATEOAS-based, globally accessible, commercially sustainable service discovery infrastructure designed for autonomous agents as its primary consumers. It specifies the governance model, the three-dimensional trust model, the APIX Manifest (APM) base format, commercial onboarding and sanctions compliance, the supply- side funding model, and the base Index API. These elements are shared across all APIX service types. Profile documents extend this core for specific service categories: the APIX Services Profile (draft-rehfeld-apix-services-01) defines the web API and bot service profile; the APIX IoT Device Profile (draft-rehfeld-apix-iot-01) defines the IoT device profile.