EUR-Lex
EUR-Lex is the European Union's official gateway to its legal texts. It holds the founding treaties, regulations and directives, judgments of the Court of Justice, and the proposals moving through the legislative process, all kept up to date as the law changes.
Every document is published in the EU's 24 official languages, which makes EUR-Lex one of the better sources for building legal RAG that works across languages. You can browse and search on the site, download documents in bulk, or work with the metadata as RDF, a format for expressing structured facts as subject, predicate, and object statements.
Reuse is authorised under Commission Decision 2011/833/EU, so you can build on the content for both research and commercial projects.
Related sources
Cambridge Law Corpus
A research dataset of more than 250,000 UK court cases, mostly from the 21st century but with some reaching back to the 16th century. Built by the University of Cambridge for legal natural language processing work, it is available under restricted access for research use.
EDGAR (SEC Filings)
The US Securities and Exchange Commission's repository of corporate filings, including annual reports (10-K), quarterly reports (10-Q), current reports (8-K), and proxy statements. You can search the full text or pull filings in bulk through an API, which makes it a rich source for financial and regulatory RAG.
Free Law Project / CourtListener
The largest open collection of US court opinions, oral argument recordings, and judicial financial disclosures, run by the nonprofit Free Law Project. Its RECAP Archive holds hundreds of millions of federal court docket entries, and journalists at the Wall Street Journal and ProPublica have used it for investigations. A solid base for US legal RAG.
Legislation.gov.uk
The official UK government legislation database, holding all UK Acts of Parliament and statutory instruments. It is available as XML and linked data, so you can load the full statute book into a RAG system rather than scraping individual pages.