# Reference (/reference)



The full API reference for headless.ly. For entity documentation, see the [Entities](/entities) tab.

Interfaces [#interfaces]

Five projections of the same verb system:

<Cards>
  <Card title="SDK" href="/reference/sdk">
    TypeScript SDK — the primary interface for agents and developers.
  </Card>

  <Card title="MCP" href="/reference/mcp">
    Three tools for AI agents: search, fetch, do.
  </Card>

  <Card title="CLI" href="/reference/cli">
    Terminal interface mirroring the SDK.
  </Card>

  <Card title="REST API" href="/reference/rest">
    HTTP endpoints for any client.
  </Card>
</Cards>

Concepts [#concepts]

<Cards>
  <Card title="Digital Objects" href="/reference/concepts/digital-objects">
    The Noun() function, typed schemas, zero dependencies.
  </Card>

  <Card title="Verb Conjugation" href="/reference/concepts/verbs">
    qualify() / qualifying() / qualified() / qualifiedBy — full lifecycle.
  </Card>

  <Card title="Events" href="/reference/concepts/events">
    Immutable event log, time travel, CDC.
  </Card>

  <Card title="Architecture" href="/reference/concepts/architecture">
    Layer stack from Cloudflare to SDK.
  </Card>
</Cards>

Integrations [#integrations]

<Cards>
  <Card title="Stripe" href="/reference/integrations/stripe">
    Truth source for all Billing entities and financial metrics.
  </Card>

  <Card title="GitHub" href="/reference/integrations/github">
    Truth source for all Projects entities.
  </Card>

  <Card title="Analytics Forwarding" href="/reference/integrations/analytics">
    Forward events to GA, Sentry, PostHog while building the lakehouse.
  </Card>

  <Card title="Dashboards" href="/reference/integrations/dashboards">
    Numerics, Grafana, Retool, and any BI tool.
  </Card>
</Cards>