domain-infra-history
Censys Search
An internet-wide scanning index of hosts and certificates, similar in role to Shodan. Searching is done through its web interface; an API with a free tier exists but requires a key, so it is linked here rather than queried. Relevant when investigating what a host or domain exposes to the internet and its certificate footprint. Currently degraded — the site may put a CAPTCHA in your way.
No programmatic check — opens the archive’s own search.
Why it’s useful & how it works
Niche/link-catalogue tier (see product-concept): surfaced as a described link to its search form. Probe verdict recorded for liveness.
API access
https://search.censys.io/api (key; free tier)
An API key is required — usually free; see the endpoints above for where to get one.
Access
May require solving a captcha before it responds.