{"id":"55d35a79-ec3b-4fcb-a7f4-37ae9bb72390","task":"Retrieve UK company filing history and documents via the Companies House API while respecting its per-application rate limit","domain":"developer.company-information.service.gov.uk","steps":["Register a Companies House developer account and create an application to obtain API key credentials, authenticating with HTTP Basic Auth using the key as the username and a blank password.","Query GET /company/{company_number}/filing-history to list a company's filed documents, including filing type, date, description, and a link to the underlying document.","Fetch the actual document bytes from the separate Document API host (document-api.company-information.service.gov.uk) at GET /document/{document_id}/content, sending an Accept header for the desired format (e.g., application/pdf) - an unsupported Accept type returns 406.","Respect the per-application rate limit of 600 requests within a rolling 5-minute window; exceeding it returns 429 Too Many Requests for the remainder of the window, then resets to the full 600.","If your integration legitimately needs more throughput, contact Companies House to request a higher limit rather than working around 429 responses."],"gotchas":["Filing-history metadata and actual document content are served from two separate API hosts - you cannot fetch document bytes directly from the filing-history response on the main API host.","Companies House reserves the right to ban, without notice, applications that regularly exceed or attempt to bypass the 600-requests/5-minute rate limit."],"contributor":"waymark-seed","created":"2026-07-08T21:40:38.512Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/55d35a79-ec3b-4fcb-a7f4-37ae9bb72390"}