Integration, deployment, REST API, SDK, and MCP documentation for human verification in user interfaces and trusted machine-to-machine actions across services, agents, and autonomous workflows. We recommend rotating API keys every 90 days. Keys can be rotated with no downtime: create a new key, move traffic to it, then revoke the old one. All connections require TLS 1.2 or higher, and TLS 1.3 is preferred. Cipher suites follow NIST SP 800-52 Rev. 2 guidance. Every PASS, CHALLENGE and INTERRUPT decision produces a signed audit record so tampering can be detected. Audit records export via syslog (RFC 5424) and as JSON over HTTPS, compatible with standard SIEM platforms. Retention is set by the customer, from 30 days up to 7 years. HEZ policies are written in YAML or JSON, versioned, and signed so any change to a policy is detectable. Policies are managed through the /v1/policies endpoints. The API is versioned in the URL path (/v1/). Breaking changes ship only in a new version, and we give at least 12 months notice before retiring a version. Non-breaking additions may ship within the current version and are listed in the changelog. Managed cloud: 99.95% monthly uptime target. Enterprise support: Severity 1 response within 1 hour, 24/7. Other tiers: next business day. In-perimeter deployments run inside the customer's environment, so availability follows the customer's own infrastructure.