# API Reference

Canonical lookup surface for the FHIR APIs Payerbox exposes. Narrative usage of each API lives in its pillar section ([FHIR App Portal](../fhir-app-portal/README.md), [Interop APIs](../interop-apis/README.md), [Prior Auth](../prior-auth/README.md)).

| Page | What it covers |
|---|---|
| [Capability Statement (/metadata)](capability-statement.md) | Live URL and downloadable JSON per API surface |
| [Implementation Guides](implementation-guides.md) | Pinned IG versions and per-release deltas |
| [Authentication](authentication.md) | SMART App Launch, Backend Services, JWKS, scopes |
| [Resources](resources.md) | FHIR resources exposed, tagged by API surface |
| [Operations](operations/README.md) | FHIR REST and named operations |