Lexiel vs Masterlex: an honest comparison of legal AI for Spanish lawyers in 2026

Masterlex is one of the newest legal AI tools on the Spanish market. It is published by MASTERLEX AI, S.L., based in Valencia according to its legal notice, and presents itself as a copilot that analyses documents, flags procedural risks and searches case law. If you are comparing options, this article covers what it does well, where we think Lexiel gives you more, and when Masterlex is the better choice. Everything we say about Masterlex comes from its public website, checked on 3 November 2026, with the links at the end.

Summary in 30 seconds

• Masterlex is web only, runs on Tirant lo Blanch case law and legislation, and has the lower entry price of the two: €29.99 + VAT a month, or €26.99 + VAT with a 12-month commitment, with 50 queries a month.
• Lexiel checks every citation against the official source (CENDOJ, the BOE) and flags the ones it cannot confirm, and adds what surrounds the query: a Word plugin, a deadline calculator with public holidays, an MCP connector for Claude and ChatGPT, and an Android app.
• If your priority is paying the least and you already trust the Tirant collection, Masterlex is a reasonable choice. If what keeps you up at night is signing a brief with a citation that does not exist, read on.

What Masterlex does well

We start here because it is fair, and because a comparison that only praises its author does not help you decide.

• The Tirant lo Blanch collection. According to its website, Masterlex has "access to Tirant lo Blanch case law and legislation" and draws on statutes, legal commentary and case law. Tirant is a leading Spanish legal publisher and its collection includes editorial commentary, which Lexiel does not offer: our case law comes from official sources (CENDOJ, the BOE, the Constitutional Court, the CJEU), not from a publisher's catalogue.
• Entry price. €29.99 + VAT a month with no commitment, or €26.99 + VAT if you accept a 12-month commitment billed monthly. The Standard plan, with unlimited queries, costs €59.99 + VAT (€53.99 with the annual commitment). It is cheaper than our Basic plan.
• A case-centred workflow. Its website describes a four-step process (you upload the case, the AI diagnoses it, proposes a strategy and drafts a document the lawyer approves), with viability analysis and procedural risk detection on every plan.
• Easy start. A 14-day free trial, sign-in with Google, Microsoft or LinkedIn, and WhatsApp support.

Where Lexiel gives you more, with facts

1. Every citation checked against the official source

Masterlex's FAQ explains that its AI works on the Tirant corpus, "so every reference, citation or analysis is strictly anchored to real legal sources". That is a sound principle, but anchoring an answer to a corpus is not the same as checking each citation one by one: a model can combine the number of one judgment with the date of another even when both exist. Its website does not say that each citation links to the ruling, nor what happens with a reference that is not in the corpus.

In Lexiel every citation goes through a verifier that looks it up in the official source (CENDOJ for judgments, the BOE consolidated legislation API for articles) and gives it one of these states: verified, pending because the source did not respond, or not confirmed because the source responded and does not contain it. The last two are never merged, because for the person signing they mean opposite things. We explain it in detail in how a verified legal RAG works.

The invented ECLI test. You can run it in a minute on any tool, ours included: ask it to comment on a judgment with a well-formed ECLI that does not exist, for example ECLI:ES:TS:2099:9999. The format is flawless, so a format check accepts it. A real verification looks it up in CENDOJ, does not find it and warns you. If the tool gives you a convincing commentary on that judgment, you know what it does with citations. More guidance in how to verify legal citations and avoid hallucinations.

2. Inside Word

Lexiel has a Microsoft Word plugin (Word 2019 or later and Microsoft 365): you draft, review and verify citations without leaving the document you are going to file. Masterlex's website does not mention a Word integration; you work in its web application.

3. Deadlines on the real procedural calendar

Masterlex's website mentions that each case keeps "its briefs, information and deadlines" and that the AI can draw up "a case action plan with milestones and procedural deadlines". Lexiel also has a procedural deadline calculator that applies the calendar of non-working days: weekends, national and regional public holidays for your autonomous community, August, and 24 December to 6 January (art. 130.2 LEC and art. 183 LOPJ as currently worded). Local holidays, for now, you need to check yourself. Why one day matters is covered in procedural deadlines: how to avoid fatal errors.

4. Lexiel inside Claude or ChatGPT (MCP)

If you already use Claude or ChatGPT, the Lexiel MCP connector gives them case law search and citation verification against the BOE and CENDOJ: 40 free queries a day with no card, or €19 + VAT a month on the Connector plan, which is included in the Basic, Professional and Firm plans. Masterlex's website does not mention an MCP connector or a public API.

5. Mobile app

Lexiel has an Android app on Google Play; the iPhone app is not on the App Store yet. Masterlex, according to its website, runs in the browser.

6. Where your query is processed

Both websites talk about the EU, and it is worth reading the small print on both. Masterlex's privacy policy states that the database and documents are hosted on EU infrastructure (Supabase) and names Anthropic, OpenAI and Google as processors of queries and documents, with transfers to the United States covered by standard contractual clauses or the EU-US Data Privacy Framework. That is a lawful and common setup. At Lexiel, according to our privacy policy, the models that process your queries, documents and briefs run on Google Cloud Vertex AI in the European Union, with no fallback providers outside it. Always ask for the list of processors, from them and from us.

Comparison table

Prices, with a date

Masterlex (checked on 3 November 2026, prices + VAT): Basic €29.99/month or €26.99/month with an annual commitment (50 queries); Standard €59.99/month or €53.99/month with an annual commitment (unlimited); Firm €53.99 per user per month, or €48.59 with an annual commitment, with a minimum of two licences according to its terms.

Lexiel: Basic €52/month + VAT billed annually or €62.40 + VAT monthly; Professional, which adds brief drafting, €74/month + VAT billed annually or €88.80 + VAT monthly. These are launch pioneer prices, valid until 31 December 2026; whoever signs up at them keeps them on renewal. All plans on the pricing page.

Masterlex is cheaper to start. To compare fairly, note that its Basic plan has 50 queries a month while Lexiel's has no cap, and that AI brief drafting at Lexiel is in the Professional plan.

When to choose Masterlex

• You already work with Tirant lo Blanch and value its editorial commentary alongside the case law.
• You run few queries a month and the entry price matters most.
• You mainly want analysis of a case you upload (viability, risks, action plan) and do not need Word, calendar-aware deadlines or a connector.

When to choose Lexiel

• You want to know, citation by citation, which ones are confirmed in the official source before you sign.
• You draft in Word and do not want to copy and paste between windows.
• You manage deadlines and need the computation to respect regional holidays, August and Christmas.
• You already use Claude or ChatGPT and want them to consult verified Spanish law.

Frequently asked questions

Does Masterlex invent citations?

We have not measured it and we do not claim it does. Its website says it works anchored to the Tirant corpus. What you can do is run the invented ECLI test described above, on Masterlex and on Lexiel, and compare the results.

Which one is cheaper?

Masterlex at entry level: €26.99 + VAT a month with an annual commitment, against €52 + VAT for Lexiel Basic billed annually. Look at what each plan includes: number of queries, brief drafting, and tools such as Word or deadlines.

Can I use both?

Yes. Some lawyers keep their publisher database and use Lexiel to verify citations and draft in Word. Lexiel's free MCP connector is a way to try it without switching tools.

Further reading

• The full market analysis: Spanish legal software comparison 2026.
• If Tirant is your reference: Lexiel vs Tirant lo Blanch.
• The underlying problem: how to verify legal citations and avoid hallucinations and procedural deadlines without errors.
• How Lexiel solves it: how Lexiel's legal RAG works and the deadline calculator.

Try Lexiel free for 14 days →

Sources on Masterlex, checked on 3 November 2026: home page and pricing at masterlex.com, privacy policy, legal notice and terms of sale. If anything has changed, write to us at hola@lexiel.ai and we will correct it.