Legal tools work better when they speak the same language. FOLIO gives them 18,000+ standard legal concepts, and these open-source tools put those concepts to work. Try each one in your browser with sample documents (no account, no API key, no upload), then build it into your own systems.
Contracts, briefs, opinions, and time entries arrive as unstructured text. FOLIO's tools turn them into structured data: every document, clause, party, and task tagged with a standard legal concept that every tool understands.
The officers used force against the plaintiff during the arrest, and the plaintiff sued under 42 U.S.C. § 1983.
The officers (Police Officer, Actor / Player) used force (Excessive Force Claim, Objectives) against the plaintiff (Plaintiff, Actor / Player) during the arrest (Arrest, Event), and the plaintiff (Plaintiff, Actor / Player) sued (Trial Court Filing Event, Event) under 42 U.S.C. § 1983 (Civil Rights, Objectives).
Describes the whole document
Illustrative sentence and tags
An LLM reads legal text well, but it names the same thing differently each time. FOLIO gives each concept one permanent ID. The LLM reads it; FOLIO names it.
Your document system, your billing system, and the courts you file in each name things their own way. California calls a motion to dismiss a demurrer. FOLIO gives each concept one permanent ID, so a single query finds every motion to dismiss across all 50 states and every system you run.
A chart needs categories that stay put. Ask an LLM to sort 10,000 matters, and it invents labels: "MTD," "Motion to Dismiss," "12(b)(6) motion." One category splits into three bars, and every percentage comes out wrong. FOLIO tags each matter with one ID, so your percentages, trend lines, and pie charts add up.
Illustrative
INPUT: an unstructured court opinion. OUTPUT: structured, well-tagged data, including its document type, legal issues, parties, and citations.
Open a sample document (e.g., timekeeping narrative, contract, brief) and watch it come back tagged with its type, its contents, and the parties, dates, and citations.
FOLIO Enrich turns an unstructured court opinion into structured, tagged data, linking each legal term to a FOLIO concept.
INPUT: your homemade tags. OUTPUT: standard FOLIO tags that every tool understands.
Bring your organization's own taxonomy, and Mapper splits each homemade tag into the standard FOLIO concepts underneath it.
FOLIO Mapper turns a firm's homemade tags into standard FOLIO concepts: Broker-Dealer Law maps to three concepts on three branches.
INPUT: a concept your practice needs. OUTPUT: a standard tag the whole community can use.
Browse, discuss, and propose changes to the FOLIO ontology itself, built in collaboration with CDCF.
An editor adds a sibling class and a synonym to a small legal-services ontology, and one save commits both.
INPUT: unstructured opinions and briefs. OUTPUT: short, tagged propositions, each tied to its source words.
Turn legal documents (e.g., opinions, briefs, statutes, textbooks, contracts) into short, tagged propositions — each tied to the exact words it rests on.
Insights runs as a preview on a small synthetic corpus.
FOLIO Insights: review propositions, follow their concepts, and upload a corpus.
INPUT: your agents and apps. OUTPUT: one shared set of 18,000+ legal tags they all speak.
Wire FOLIO into your own agents, apps, and pipelines.
MCP setup command: claude mcp add folio -- uvx folio-mcp. Illustrative tagged result: concept Motion to Dismiss, IRI https://folio.openlegalstandard.org/R9Xkp4FqX83NG5ZI0CDfQ1k, label Motion to Dismiss.
Pick your role to see what FOLIO does for you: KM and Innovation, Law-Firm Lawyers, Corporate Law Departments, Government Lawyers, Legal Aid Organizations, Courts, and Legal Technology Companies.
Stop maintaining a homemade taxonomy that your various tools don't understand.
Find the legal concept, the clause, the holding, or the issue faster — in documents you already have.
Know all your in-flight questions and matters; know what your contracts say before the next deal, audit, or dispute.
Triage complaints, charges, and filings by issue, with the same tags in every office.
Build upon your clients' and tools' 18,000+ standard legal concepts — instead of re-inventing the wheel.
Practicing law takes law and facts. FOLIO covers the law; a companion project, OpenGloss, covers the facts.
OpenGloss, a companion project by Mike Bommarito. An open-source dictionary, encyclopedia, and knowledge graph of 150,000 everyday concepts, with definitions, senses, synonyms, and 9.1 million links between them. Visit opengloss.com, read the paper, and download the data from Hugging Face.
Explore all 18,000+ concepts in the browser, download FOLIO.owl, or fetch any concept as HTML, RDF, Markdown, or JSON. Try Motion to Dismiss or Murder.
Learn how FOLIO connects legal information.
Browse the ontology.
Find FOLIO source repositories.
Download the ontology from its repository.
Retrieve concepts in several formats.
Read about the API and MCP tools.
The FOLIO ontology and all of its tools are free and open source. Pick the connection that fits your stack.
