Silex vs. CASUS: CASUS is the more complete choice for Swiss law firms and legal departments that want legal research to flow directly into document work: in Microsoft Word, in matter-based dossiers and across large document sets. Silex is a focused alternative for source-backed Swiss legal research and a data infrastructure described as entirely Swiss. For an end-to-end legal workflow, our overall recommendation is CASUS.
CASUS and Silex at a glance
Criterion | CASUS | Silex |
|---|---|---|
Legal research | More than 660,000 Swiss court decisions, plus federal and cantonal law | Research based on official Swiss legal sources; the provider lists legislation, decisions, doctrine and regulatory materials |
Microsoft Word | Dedicated Word Add-in for drafting, reviewing and editing documents | DOCX and PDF export documented; no Word Add-in documented on the public pages reviewed |
Document work | Web application and Word Add-in for drafting, reviewing and editing | Drafting, anonymisation, translation and document comparison described as platform functions |
Multiple documents | Dossiers for up to 1,000 documents; separate AI Data Room for tabular analysis of collections containing thousands of documents | Internal knowledge through Silos; a document-comparison agent is described |
Data location | Client matter content and workspace data in Zurich; AI inference in EU or Swiss regions | Storage and processing described by the provider as entirely in Switzerland |
Public individual price | CHF 145 per user per month or CHF 1,440 per year | CHF 149 per month or CHF 1,440 per year for Solo |
Trial | 14 days free | 7 days free, without a credit card according to the provider |
Information was checked on 8 September 2026. Prices exclude VAT. Features and terms should be rechecked before purchase.
The key difference: from research result to finished document
Both products support research into Swiss law. The most important difference appears after the answer has been found: what happens next?
Silex describes a research-first workflow. It addresses legal questions using Swiss sources, provides citations and can turn an answer into a first draft. According to its product page, memos, letters and clauses can be exported as DOCX or PDF. Silex also describes agents for tasks such as anonymisation, translation and document comparison, as well as Silos for internal knowledge.
CASUS connects research more closely with subsequent document work. The CASUS Word Add-in brings legal AI into an open Microsoft Word document. Legal professionals can draft, review and edit text there without first transferring research results from a separate application. Documents stored in SharePoint can be opened in Word Online or the desktop application and worked on with the Add-in.
Teams that continue their work in Word after research benefit from bringing sources, document context and proposed edits closer together. Teams that primarily need a sourced answer to a Swiss legal question may find the more focused Silex workflow sufficient.
Swiss legal research: a shared strength
CASUS Legal Research provides access in its web-based research workflow to more than 660,000 Swiss court decisions, plus Swiss federal and cantonal law. The supported court selection includes the Federal Supreme Court, Federal Administrative Court, Federal Criminal Court, Federal Patent Court and cantonal courts. The number refers specifically to court decisions; federal and cantonal law are separate source categories.
Silex describes research based on official Swiss legal sources and lists federal and cantonal legislation, court decisions, doctrine and regulatory materials. It says answers can be scoped by canton, field of law and source type. Silex lists German, French, Italian and English for translation, which does not establish identical research coverage in all four languages.
A sensible pilot should use the same representative questions in both products and open every material citation in the original source.
CASUS publicly defines its Swiss case-law scope, while Silex also lists doctrine and regulatory materials. The sources needed for a particular practice area, canton or matter should be tested in both products.
Microsoft Word: integration rather than subsequent export
Legal work rarely ends in a chat. It ends in a pleading, contract, memorandum or internal opinion. That makes the relationship between a legal AI product and Microsoft Word a material buying criterion.
CASUS offers a dedicated Word Add-in for trained legal professionals. It supports drafting, reviewing and editing documents directly in Word. The open document remains the working context, and proposed edits do not first have to be copied from a browser and reformatted. Anonymisation can also be performed in the open document: personal identifiers can be replaced systematically or with consistent pseudonyms, and the result can be applied directly.
Silex documents the creation of drafts and their export as DOCX or PDF. Its current FAQ describes text-based PDFs for document uploads and says support for Word files is planned for a later version. A Microsoft Word Add-in is not documented on the product, pricing or FAQ pages reviewed. This does not prove that a non-public or customer-specific integration cannot exist. For the publicly documented standard workflow, however, the distinction is clear: CASUS works inside the Word document, while Silex describes exporting a Word file.
For teams that edit contracts or substantial pleadings every day, this is a meaningful CASUS advantage. A pilot should still test document fidelity, formatting and traceability.
From individual documents to complete matters
CASUS Dossiers are designed for matter-based work with up to 1,000 documents. Users can analyse the full dossier across any number of chats, with references back to the underlying material. Typical use cases include large document reviews, knowledge management and due diligence.
For tabular review of larger collections, CASUS offers a separate AI Data Room. This is distinct from Dossiers, has no fixed product-level cap on the total number of documents in a data room and can analyse collections containing thousands of documents using consistent questions and extraction fields. No fixed document-count cap does not mean unlimited technical capacity: file, storage, usage and processing constraints can still apply.
Silex describes Silos that can bring internal documents into answers and an agent for comparing legal documents. The reviewed public pages do not describe a directly comparable tabular data-room workflow for collections containing thousands of documents.
For legal teams that want AI to serve not only as a search interface but as a shared workspace for matters and large reviews, CASUS is therefore the more complete option.
Data protection and professional secrecy
CASUS stores client matter content and workspace data in the Google Cloud Zurich region. AI inference takes place in EU or Swiss regions. CASUS and its model providers do not use customer data to train or fine-tune models. Zero-data-retention arrangements are in place for the documented LLM flows.
Silex describes its storage and processing as entirely Swiss. Its security page states that data at rest is encrypted and customer content is not used to train AI models. This is a strong and straightforward position for organisations that define Swiss-only infrastructure as a mandatory procurement criterion.
The approaches should not be reduced to "secure" versus "insecure". Before purchase, organisations should review the data-processing agreement, subprocessors, retention, support access and the specific configuration for either provider.
Price and value
CASUS Standard costs CHF 145 per user per month in Switzerland or CHF 1,440 per user per year. CASUS Advanced is intended for organisations and is offered on request. Its current description includes SSO, access controls, advanced workflows and integrations, SLA and priority support.
Silex Solo costs CHF 149 when billed monthly or CHF 1,440 per year. The plan includes one licence, ten agent credits per month, 20 GB of Silo storage, legal research described as unlimited, all AI agents and connected applications. Agent credits apply to running agents and are distinct from legal research.
The public annual list price is therefore the same. CASUS does not win the comparison through a lower annual price, but through the value delivered to teams that need research, direct Word work, Dossiers and a separate multi-document workflow in one product. Silex may offer the better value where the need is concentrated almost entirely on Swiss research and Swiss-only data handling.
CASUS offers a 14-day free trial. Silex states that its standard trial lasts seven days without a credit card. Both should be tested with completed matters and original-source checks.
Who may prefer Silex
Silex is a credible choice for teams primarily seeking focused Swiss legal research, internal knowledge and an entirely Swiss infrastructure.
CASUS is a better fit when several stages of work need to be connected: research, drafting and review in Word, matter-based document collections and structured analysis across large sets. For that broader requirement, CASUS is the more complete choice in our view.
How to compare both products
Ask the same three to five Swiss legal questions drawn from completed matters.
Open every material citation and verify that it supports the specific statement.
Work on the same complex Word document and record copy-paste, formatting and rework.
Test a typical matter file and, where relevant, a large data room using identical extraction questions.
Compare data regions, retention, subprocessors, roles and support access for the configuration actually offered.
Calculate annual costs using realistic user numbers and the additional services your team actually needs.
AI output can be incomplete or incorrect. Results and sources must be reviewed by a legally trained person before use.
Our recommendation
Silex and CASUS are both serious Swiss legal AI products, but they emphasise different parts of the workflow. Silex is particularly relevant for focused, source-backed research and Swiss-only infrastructure.
For most law firms and legal departments, however, work does not end with a researched answer. Documents still need to be drafted, reviewed, revised and considered alongside extensive matter files. CASUS connects these stages with Swiss legal research and works directly in Microsoft Word. At the same public annual price, CASUS provides the stronger overall value for this broader workflow.
Try CASUS for free using your own legal questions and documents.
Frequently asked questions
Is CASUS a good alternative to Silex?
Yes. CASUS is particularly suitable when Swiss legal research needs to connect with direct work in Microsoft Word, matter-based Dossiers and the analysis of large document collections. Silex is more tightly focused on a Swiss research workflow and Swiss-only infrastructure.
What is the main difference between CASUS and Silex?
The main difference is the transition from research result to subsequent document work. CASUS provides a dedicated Microsoft Word Add-in and separate workflows for Dossiers and large data rooms. Silex describes research, drafting, DOCX/PDF export, document agents and internal knowledge Silos.
Do CASUS and Silex support Swiss legal research?
Yes. CASUS provides access to more than 660,000 Swiss court decisions, plus federal and cantonal law. Silex describes research based on official Swiss legal sources and lists legislation, case law, doctrine and regulatory materials. Legal quality should be compared using identical questions and original-source review.
Which product works directly in Microsoft Word?
CASUS offers a dedicated Word Add-in for drafting, reviewing and editing documents. Silex documents the export of drafts as DOCX or PDF; a Microsoft Word Add-in is not described on the public product, pricing and FAQ pages reviewed. Any non-public integrations should be clarified in the proposal.
How much do CASUS and Silex cost in Switzerland?
CASUS Standard costs CHF 145 monthly or CHF 1,440 annually per user. Silex Solo costs CHF 149 monthly or the same CHF 1,440 annually for one licence. Prices are net or exclude VAT and were checked on 8 September 2026.
Where do CASUS and Silex store and process data?
CASUS stores client matter content and workspace data in Zurich, with AI inference in EU or Swiss regions. Silex describes storage and processing as entirely in Switzerland. Current contracts, subprocessors and the proposed configuration should be reviewed for either product before purchase.
