Private legal AI · Built in the EU
The private AI workspace for legal teams.
Gaius-Lex reviews contracts, answers legal questions with checked citations and automates the work your team repeats. It runs in our EU-only cloud or on an appliance in your office, and your documents are never used to train a model.
- For in-house legal teams, law firms and tax advisors
- Processing only in the EU, or fully offline
- Encryption post-quantum, on every account
- Every citation checked before you rely on it
Supply agreement review Gaius Vault · on-premise Can the supplier terminate before the end of the term?
Only for the reasons listed in Annex 2. Clause 14.2 limits early termination to that list. The reason given in the supplier’s letter of 26 September is not on it. Two points need your decision.
- Agreement, clause 14.2Your documents · ✓ verified
- Annex 2, item 4Your documents · ✓ verified
- Civil Code provisionGaius-Lex legal database · ✓ verified
- Supreme Court judgmentData partner · ✓ verified
What it is
An AI workspace for legal work: contract review, research with sources and automation of repeat tasks.
Who it is for
Legal departments, law firms and tax advisors, above all in regulated organisations such as banks, insurers and the public sector.
Where it runs
Gaius-Lex Cloud, processed only in the EU, or Gaius Vault, an appliance in your office that works fully offline.
Our focus
We build the product. Partners roll it out.
Legal AI projects stall on two questions: can we trust the answer, and may our files leave the building. That is what we build for: a ready product with its own legal database, which a legal team can use directly or an implementation partner can deploy for its clients.
What Gaius-Lex builds.
- The workspace lawyers use every day, in the browser, Word, Outlook, Gmail and on the phone.
- Document work: contract analysis, prohibited-clause detection, checks against your own rules, OCR.
- Gaius Agent and skills that turn a team’s procedures into tools anyone can run.
- Citation verification that opens each cited source and confirms it says what the answer claims.
- Private deployment in an EU-only cloud or on an appliance in your office.
- Our own legal database, searched together with your documents.
Ready to deploy for your clients.
- A finished product, not a toolkit. Your team configures and rolls it out instead of building a legal layer from scratch.
- Cloud or on-premise. The same product in our EU cloud or on an appliance in the client’s office.
- Our team behind yours. Security documentation, skill onboarding and workshops for the client’s lawyers.
Product
What a legal team does in Gaius on day one.
Each capability is a screen in the Gaius app and an endpoint in the API.
01 · Documents
Work on the files you already have.
- Contract analysis: risks, obligations and deadlines across a whole contract.
- Prohibited-clause detection in consumer terms.
- Document verification against your rules or checklist.
- Encrypted drive with semantic search and OCR.
02 · Research
Answers that lead to a source.
- Answers with citations to a provision, judgment or case number.
- Citation check on any document, including drafts from others.
- Thesis analysis: test an argument against case law.
- Company registries pulled straight into the matter.
03 · Automation
Turn practice into a repeatable tool.
- Gaius Agent: search, read and draft in one run.
- Skill builder for your own procedures, such as NDA review.
- Rule analysis: a regulation broken into obligations. Beta.
- Workshops with the team that built the product.
How it works
Every answer is checked before you see it.
The check runs on every source in the answer, whether it comes from our database, a data partner’s collection or your own files.
- 1ClarifyAsks for missing facts, such as the contract type or the relevant date, before it searches.
- 2RetrieveKeyword and semantic search across connected sources, merged and re-ranked.
- 3WeighHigher courts above lower, provisions in force on the date that matters above amended ones.
- 4DraftEvery statement links to the passage that supports it.
- 5VerifyA separate pass opens each cited document. Anything it cannot confirm is flagged.
Deployment
Two ways to run it. The same platform in both.
Start in the cloud and move on-premise later: the same API, the same skills, the same integrations.
Gaius-Lex Cloud
Hosted by us. Live in days.
- All processing in the EU.
- Files encrypted with keys held by users.
- New features and sources without an upgrade project.
Fits: pilots, growing legal teams, organisations without their own GPU infrastructure.
In your office. Nothing leaves.
- An appliance with AI models and legal sources preinstalled.
- One IP address in your LAN. Runs fully offline.
- Updates only through a relay you control.
Fits: banks, insurers, regulated in-house teams, any policy that bars external models.
Post-quantum encryption, on for every account.
Documents are protected against today’s attacks and against “harvest now, decrypt later”. Keys stay with the user, with backup codes instead of a master key on our side.
Where it opens
No new window to learn.
Adoption is where most legal AI projects stall. Gaius opens in the tools lawyers already have on screen every morning.
- Gaius web app Chat, drive, tools and history in one place.
-
Word Research and review beside the draft. -
Outlook Work on attachments without downloading them. -
Gmail Analyse what arrives, answer from the inbox. -
SharePoint Connect the libraries where matters live. -
OneDrive Personal files, same permissions. -
Google Drive Shared drives, searchable from Gaius. -
Gaius Meet Google Meet transcripts straight into the matter. -
Android Scan a document in court, ask about it on the way back. -
iOS The same workspace on iPhone and iPad.
Benchmarks
Our retrieval beats the published state of the art.
An answer is only as good as the passages it finds. We tested Gaius-Lex retrieval against three classes of systems. The same search runs on every source you connect: our database, a data partner’s collection or your own files.
vs agentic search
+5.1 points over the state of the art.
A model that searches the corpus with terminal tools instead of semantic search.
vs hybrid search
+2.3 points over the best embedding model.
Semantic and lexical search with leading embedding models, run on Vespa.
vs modern retrieval models
+1.7 points over the best model reported.
Retrieval models as reported in the GIRCSE paper.
Retrieval scores on a 0–100 scale. Results of 8 July 2026.
Partners
Three ways to work with Gaius-Lex.
Lawyers using Gaius-Lex Cloud.
Sign up and work on your own matters straight away: research with checked citations, contract review and drafting, in the browser, Word or on your phone. Nothing to install.
Start in the cloud →Integrators and software consultancies.
Deliver legal AI to enterprise clients on our API: search, answers, the agent and document analysis. We answer the client’s security questionnaire with you.
See the API →Advisory firms and resellers.
Offer Gaius Vault to your clients, with our team behind the installation, workshops and support.
Become a reseller →API
Every capability in the app has an endpoint.
Connect Gaius to a document management system, a contract lifecycle tool or an intranet. Long tasks run as jobs and report back by webhook or polling. Each integration gets its own key, so it can be revoked on its own.
- search
- answer
- agent
- doc-verification
- anonymization
- ocr
- abusivity
- registries
# Ask a question, fetch the answer by id
curl -X POST https://api.gaius-lex.pl/api/v1/answer/poll \
-H "Authorization: Api-Key $GAIUS_API_KEY" \
-d '{"question": "Can the supplier terminate
a fixed-term agreement early?"}'
curl https://api.gaius-lex.pl/api/v1/answer/poll/<uuid> \
-H "Authorization: Api-Key $GAIUS_API_KEY"Documentation for your procurement.
Questions we hear first.
- Is Gaius-Lex a legal database?
- No. Gaius-Lex is a workspace for legal work. It comes with our own legal database and can connect specialist data providers. Every source shows where it comes from.
- Which jurisdictions are covered?
- Tell us where you operate and we confirm which sources are available, ours or a partner’s, before the project starts.
- Do you train models on our data?
- No. Documents and prompts are used only to answer your queries.
- Can we search our own documents?
- Yes. They are encrypted, only their owner has access, and with Gaius Vault they never leave your network.
- Can we start in the cloud and move on-premise later?
- Yes. The API, skills and integrations are the same in both.
Tell us what your legal team needs.
We reply with a short demo on your own documents and a proposed set-up, cloud or on-premise.