No credit card, no approval wait. One key per email, instant. 300 requests/minute (vs. 30/minute unauthenticated). Email verification and usage dashboards are coming later. For now, this just works.
Pass it as a header on every request:
curl https://dunmoreresearch.com/api/v1/entities?state=CA \ -H "x-api-key: dm_live_..."
Full reference at /docs.