Masterlex enters the legal AI market with legislation and case law from Tirant lo Blanch

The Spanish market for artificial intelligence applied to law has a new operator. Masterlex, a platform aimed at lawyers and law firms, has started its activity combining generative AI with access to legislation and case law from the Tirant lo Blanch Group, Lawyerpress reported on 21 October.

The tool, developed on the initiative of David López Algaba, is designed to speed up legal research with answers grounded in legal sources: searching for regulations, consulting judicial decisions and preparing cases. According to the company, it incorporates rulings from Provincial Courts and High Courts of Justice, as well as regional legislation, aiming to cover the particularities of the Spanish legal system.

Speed, but with sources

The proposal directly targets the profession's main objection to generative AI: reliability. "Artificial intelligence is changing the way lawyers work, but we believe the real innovation is not just getting fast answers, but answers grounded in reliable legal sources," explains López Algaba, founder of Masterlex.

The approach fits what the profession has been demanding: the deontological circular on verifying AI-generated documents and the sanctions imposed by several courts on lawyers who cited non-existent case law have turned source traceability into a deontological requirement, not a luxury. We covered this in Fines for lawyers over AI hallucinations and in The deontological circular on AI and document verification.

1,200 users in the first month

Masterlex began operating on 16 September 2026 and, according to data provided by its managers, more than 1,200 users have tried the platform since then. The company has not detailed how many maintain regular use or have contracted the service, a relevant distinction in a market where free trials inflate adoption figures.

The tool targets both independent lawyers and firms incorporating AI into their processes, especially in case preparation, case analysis and legal research.

What it means for the technology buyer

For the firm evaluating tools, the arrival of a new operator with Spanish editorial content reinforces a trend: value is shifting from the language model to the documentary corpus and verifiability. Before contracting, the relevant question is no longer only what the tool answers, but where each statement comes from and whether it can be checked with a click. Our guide to clauses when contracting an AI provider covers the rest of the due diligence.

Regional coverage as a selling point

One of the most relevant details for practice is the inclusion of regional legislation and rulings from Provincial Courts and High Courts of Justice. Much of firms' daily work is not decided at the Supreme Court but in that intermediate layer of the legal system, and that is where generalist tools fail most. If the announced coverage consolidates, it will be one of the elements to examine in any comparative test.

A market filling with specialised operators

The launch comes at a time of intense competition among legal technology providers, where generalist tools coexist with specialised solutions integrating databases of legislation, case law and doctrine. Differentiation is increasingly played on the ability to accompany each answer with verifiable references and on documentary coverage of the Spanish legal system, including regional rules.

In this context, checking sources and the legal assessment of each matter remain with the professional: responsibility for the document lies with the lawyer who signs it, as we recalled in AI and professional secrecy: client data. And for the general state of adoption, our analysis of the Tirant study: 78 % of lawyers already use AI. All sector coverage, in our Legal AI section.