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Dura Lex is an open-source operating system for legal data.
It structures public legal data — legislation, case law, company registries, administrative guidance — into a jurisdiction-agnostic corpus, queryable by AI agents via MCP and by humans via a web portal.
A jurisdiction-agnostic kernel, jurisdiction plugins (France and EU today, designed for any country), a robust ingestion pipeline, and services on top. The schema follows the OpenStreetMap model — six universal structural kinds, JSONB tags, zero schema migration to add a jurisdiction.
Everything is published as Python libraries (MIT). The kernel, the corpus protocol, the jurisdiction drivers, the ingestion framework — all are composable packages that can be embedded in any application. Use the MCP server as-is, or import the libraries directly to build your own legal data product.
Software licensed under MIT. Enriched data licensed under ODbL.
Navigation
| Section | Description |
|---|---|
| Philosophy | Why Dura Lex exists — safety, transparency, sovereignty, professional secrecy |
| Architecture | How the pieces fit together — kernel, drivers, pipeline, services |
| Corpus | The data model — schema, tags, edges, quality, temporal versioning, FTS |
| Sources | Data dictionary — one page per ingest source, coverage matrix |
| Jurisdictions | Legal systems we cover and how they map to the unified schema |
| MCP | The public API — tools, safety guidelines, reference resolution |
| Development | For contributors — coding conventions, testing, packaging |
| Design decisions | Architectural decision records (coming soon) |
Current data
France is the first implementation. The architecture is designed for any jurisdiction.
| Jurisdiction | Data | Volume |
|---|---|---|
| France | Court decisions | 3.4M |
| Legislation articles | 1.8M | |
| Collective agreements | 299K articles + 382K enterprise agreements | |
| Administrative doctrine | 9.6K | |
| Companies | 24.2M | |
| Directors | 15M | |
| Cross-citations | 4.4M links | |
| EU | CJEU decisions | — |
| ECHR decisions | — | |
| EU legislation (regulations, directives, decisions) | — |