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Prepare opinions, rulings, and client answers faster.

Gaius-Lex for Tax Advisors

Faster tax research, stronger opinions, and a complete picture of tax risk in your practice – from the first client question to disputes before the Voivodeship Administrative Court and the Supreme Administrative Court.

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Secure processing in the EEA • Encryption • Anonymization • No model training on your data

Why tax advisors choose Gaius-Lex

One tool for tax research, opinions, and disputes

Speed up your tax research, organize client documents, and strengthen your arguments in opinions, ruling applications, and disputes – using modules designed for the work of a tax advisor.

Tax research and compliance in one place

Chat with Gaius, Interactive Search, Legal Library, and DeepResearch reduce the time spent on research in Polish tax law and EU law, and help you prepare tax opinions, recommendations, and client answers faster.

  • Faster tax opinions and recommendations for clients
  • Complete picture of case law and ruling practice (Voivodeship Administrative Court/Supreme Administrative Court, National Tax Information rulings)
  • Answers always with linked sources – easier to defend your position
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Contracts and client documents under control

Analyze Contract, Analyze Theses, Write Document (in progress), and My Drive help you analyze contracts, transfer pricing documentation, tax procedures, and other client documents faster, while maintaining consistent templates across your firm.

  • Search for clauses carrying tax risk
  • Automatic extraction of theses from long opinions, rulings, and correspondence
  • Drafts of new documents based on your templates and previous cases
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Disputes, tax audits, and client materials

DeepResearch, Document Verification, Workflows, and Chat with Gaius support the preparation of strong responses to tax authority correspondence, complaints to the Voivodeship Administrative Court/Supreme Administrative Court, and synthetic client materials with the ability to verify every citation.

  • Faster analysis of authority correspondence and client arguments
  • Reports with justification of why specific judgments/rulings are key
  • Stronger positions before tax authorities and administrative courts
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Gaius-Lex modules for tax advisors

Combine tax research, client document analysis, and your own knowledge base in one tool – without switching between systems.

  • Gaius Agent

    Ask questions about Polish tax law, EU law, the Tax Ordinance, VAT/CIT/PIT, Voivodeship Administrative Court/Supreme Administrative Court case law, and tax rulings in natural language, and Gaius-Lex will return an answer with linked sources, drawing from a database of over 3.5 million documents.

  • DeepResearch

    For key topics – such as VAT changes, Estonian CIT, WHT, or taxation of cross-border transactions – launch DeepResearch, which will identify the most relevant documents, explain why they matter, and prepare a report ready to use in an opinion or correspondence with an authority.

  • Analyze Contract and Theses

    Automatically sift through long contracts, tax opinions, ruling applications, and audit protocols: Gaius-Lex will identify clauses carrying tax risk, extract key provisions, and pull out theses, marking them as strong, weak, or disputable.

  • My Drive, anonymization, and encryption

    Build your firm's own knowledge base: upload PDF files, DOCX files, scans, and recordings, use OCR and transcription, anonymize client data, and collaborate in encrypted shared folders.