About

About OpenCaseLaw

OpenCaseLaw is the largest open dataset of Swiss case law and the first LLM-ready interface to federal and cantonal legislation. Free to use, updated daily, independently funded.

§01 Mission

Mission

Swiss legal research today is fragmented, mostly behind paywalls, and hard to reach for language models. The result: law students paying for expensive commercial databases, and LLMs hallucinating article text because they have no authoritative source.

OpenCaseLaw makes publicly published Swiss court decisions and the current text of relevant statutes freely available in a searchable, citation-linked, machine-readable format — for research, teaching, practice, and AI agents.

§02 Methodology

Methodology

  • Sources: 58 scrapers covering the Federal Supreme Court, Federal Administrative Court, Federal Criminal Court, regulatory decisions (FINMA, ComCo, FDPIC, IndepBC, ElCom, etc.) and all 26 cantons. entscheidsuche.ch as a fallback source.
  • Deduplication: docket normalisation, text similarity (MinHash), regeste priority. Prevents duplicates without ever sacrificing completeness.
  • Indexing: SQLite FTS5 with BM25 ranking. Full daily rebuild, atomic swap, zero downtime for MCP workers.
  • Citation graph: 9.0M edges between decisions, 11.6M references to statute articles. Bidirectional, with appeal-chain resolution.
  • Search: BM25 + Reciprocal Rank Fusion + meta-harness tuning + Haiku reranking. MRR@10 = 0.647 on a 100-query golden set (online, March 2026).
  • Legislation: ~5,500 federal laws from the Fedlex SPARQL endpoint (~133,468 articles in DE/FR/IT), mirrored locally daily and indexed with SQLite FTS5. Cantonal and intercantonal acts via the LexFind JSON API — mirrored locally for all 26 cantons.

Full technical documentation in the GitHub repository.

§03 Numbers

Numbers

972'000+
decisions
114
courts
5'000+
federal laws
30'000+
cantonal acts
9.0M
citations
23
MCP tools

§04 License & citation

License & citation

  • Data: CC0 1.0 Public Domain — Swiss court decisions are public documents.
  • Code: MIT License (github.com/jonashertner/opencaselaw).
  • Commentaries: CC-BY-4.0 (OnlineKommentar.ch); CC BY-SA for the text of the Kommentar zur Schaffhauser Verwaltungsrechtspflege (EIZ Publishing).

Use without attribution is allowed, but appreciated: "Source: OpenCaseLaw.ch". For academic use, please cite the accompanying paper (Zenodo entry coming).

§05 Contact

Contact

Built and operated by Jonas Hertner, independently and with no commercial interest. Feedback, bug reports, and contributions welcome.

Email: team@jonashertner.com
GitHub: github.com/jonashertner/opencaselaw
LinkedIn: linkedin.com/company/opencaselaw-ch