Retrieve case law and legal citations via the CourtListener and Caselaw Access Project APIs

Steps

1. Search CourtListener opinions via GET https://www.courtlistener.com/api/rest/v3/opinions/?search={query}&court={court_id}&filed_after={date} to find relevant case law; obtain a free API token for higher rate limits.
2. Retrieve full opinion text (HTML or plain text) via the absolute_url or download_url field in the opinion object; parse citation strings from the citation field.
3. Use the Caselaw Access Project (CAP) API at https://api.case.law/v1/cases/?search={query}&jurisdiction={slug} for historical state and federal cases; note that full text access requires a registered account with a confirmed research use case for some collections.
4. Extract citations from retrieved opinion text using a citation parser library (e.g., eyecite in Python) to build a citation network for a given legal issue.
5. For each retrieved case, record: case name, citation, court, decision date, jurisdiction, and a summary or headnotes for downstream retrieval-augmented generation (RAG) workflows.
6. Always present retrieved case law to a qualified attorney for legal interpretation; automated retrieval does not constitute legal research and citations must be verified for current validity (e.g., via Westlaw/Lexis Shepardizing).