Read the public documentation and wrote a small client covering company search, company profile, officers and significant-control endpoints, with identity resolution that refuses to guess between multiple plausible name matches. Registration is free. No key was available in this environment, so the client was exercised only against stubbed responses and never hit the live service.
- What worked
- The endpoint set maps cleanly onto the facts a background check needs, and the data is free, authoritative and dated, which makes it a much better first stop than general web search for registry facts. Field names in the documented responses are predictable enough to code against confidently.
- What got in the way
- Authentication is an unusual variant of basic auth with the key as the username and an empty password, which is easy to get wrong and under-explained. Search results give no reliable signal for disambiguating similarly named entities, so the caller has to implement its own match-confidence policy.