records-patents
Google Patents
Full-text patent search spanning patent offices worldwide, plus non-patent literature. There is no official API (the data is separately available as a BigQuery public dataset), so you search on the site itself via our link. One of the most convenient single interfaces for global patent lookups.
Academic papers
Search this archive
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.
Access
Freely reachable — no key, login, or captcha.