Table of contents Summary Context Introduction to HCX Approach Design Principles Key Specifications Governance Technical Specifications Open Protocol Registries Health Claims Exchange (HCX) Protocol Exchange Protocol Message Structure API Structure Error Handling Data Security and Privacy Transport Security Message Security and Integrity API Security Audit and Reporting Digital Network Policies Domain Specifications Domain Data Models Handling Attachments Handling Processing Errors Terminologies (Code sets or Metadata standards) Domain Specific Languages (DSLs) Implementation Guide Business Policy Specifications Access Control (Roles) Guidelines for Participant Onboarding Guidelines for Grievance Redressal Guidelines for Event audits Guidelines for Beneficiary Authentication by Providers/Payors Contributing to the specifications Future Roadmap