An honest comparison The private ChatGPT alternative for businesses that keep their data.
ChatGPT, Microsoft Copilot and Mistral Le Chat are strong tools. But they run in their vendor’s cloud and are billed per person per month. Butler is the other way: an AI workspace on servers you know — at TU Wien, or in your own building. Here is the comparison, point by point, including the cases where a cloud assistant is the better choice.
- No US cloud
- Never used for training
- One-time price, not per seat
At a glance
Butler and cloud assistants, side by side.
The right-hand column describes the category, not a single product: features and terms vary by vendor and plan.
Where data is processed
Butler
Depends on the version: at TU Wien in Vienna (subscription), on your premises with heavy AI at TU Wien (portable), or entirely on your premises (complete). Never in a US cloud.
Cloud assistants (ChatGPT, Copilot, Le Chat)
In the vendor’s data centres. ChatGPT and Copilot come from US companies, Le Chat from a French one.
Used for training
Butler
Never — in any version.
Cloud assistants (ChatGPT, Copilot, Le Chat)
Business and enterprise tiers typically exclude it by contract; on free and personal tiers it often depends on a setting.
Works offline
Butler
Yes, with the complete version.
Cloud assistants (ChatGPT, Copilot, Le Chat)
No, an internet connection is required.
Meeting transcription with speaker names
Butler
Yes: Whisper large-v3 and speaker detection on its own GPUs; voices you teach it are recognised by name. Works with any meeting app.
Cloud assistants (ChatGPT, Copilot, Le Chat)
Depends on the product and plan, often tied to the vendor’s own meeting platform.
Editing Word, Excel and PowerPoint in place
Butler
Yes: Butler edits the real file and hands it back with its formatting intact.
Cloud assistants (ChatGPT, Copilot, Le Chat)
Varies: Copilot works inside Microsoft 365; other assistants tend to generate or analyse files rather than edit them in place.
Your own document database with cited answers
Butler
Yes: the Database Explorer — every answer cites the passage it rests on.
Cloud assistants (ChatGPT, Copilot, Le Chat)
Available in various forms — with the documents stored in the vendor’s cloud.
Pricing model
Butler
One-time price including hardware: portable from €5,000, complete from €25,000. Subscription by invitation, large institutions on quote.
Cloud assistants (ChatGPT, Copilot, Le Chat)
Subscription per user per month; the cost grows with every person.
Third-party information reflects generally known characteristics of the product category. Check each vendor’s current terms.
What is different
More than a chat: one tool instead of five subscriptions.
A cloud assistant is first of all a chat window. Butler brings together the work teams otherwise subscribe to several services for — on one machine, for one price.
Meetings with names
Upload a recording or capture the call: Butler writes down who said what and turns it into a report in Word or PDF.
Office files stay Office files
Correct a contract, rework a spreadsheet, translate slides: Butler changes the file itself, keeping formatting, charts and layout.
Answers with evidence
The Database Explorer reads your documents; every answer points to the passage it relies on — one click and you see the source.
Websites, archived
The Web Vacuum saves whole websites with their images and linked documents, searchable and answerable even after the original disappears.
To be fair
When a cloud assistant is the better choice.
Butler is not the right answer for everyone. In these cases ChatGPT, Copilot or Le Chat will probably serve you better:
You need the very largest models
Butler runs open-weight models on its own GPUs. The big vendors’ latest frontier models run only in their cloud.
Your work lives in Microsoft 365
If your team wants AI right inside Outlook and Teams, Copilot is at home there, where Butler stands alongside.
You work with public content
For marketing copy, general knowledge and brainstorming with no confidential data, where the data is processed hardly matters.
One or two people, now and then
For very small, occasional use, a monthly plan costs less than a machine of your own.
Butler pays off where confidential data, meetings and documents are involved — and where many per-seat licences get expensive.
Switching
How to switch without disrupting the work.
Butler does not import a ChatGPT history. What you bring along is your documents, your proven instructions and your way of working.
- 1
Start with one team
Pick an area that handles confidential data — management, HR, research — and run both tools side by side for a while.
- 2
Load documents into a database
Policies, contracts, reports: upload them once, then question them in the Database Explorer, with sources.
- 3
Save instructions as assistants
The prompts that worked in ChatGPT become assistants in Butler that the whole team can use.
- 4
Write down the rules
Decide which data may go where and document it — our page on AI and the GDPR includes a checklist.
Questions
Is Butler as good as ChatGPT?
For top performance on open-ended general knowledge, the largest cloud models lead. For work on your own documents, meetings and Office files, what matters most is that the AI may see your data — and with Butler that is not a problem.
Is Butler GDPR-compliant?
Butler is built for the GDPR: no US cloud provider, no training, deletion under your control. Whether your processing complies is for you to establish with your data protection officer.
Do ChatGPT and Copilot train on my data?
On business and enterprise tiers the vendors typically exclude it by contract. On free and personal accounts it often depends on the settings. Butler never trains on anything.
What does Butler cost by comparison?
Instead of a price per person per month, you pay once: portable from €5,000, complete from €25,000 for up to 50 people, hardware included. We are happy to work out how that compares with your licences.
Can we use Butler and Copilot side by side?
Yes. Many organisations keep a cloud assistant for non-sensitive work and use Butler for everything that must not leave the building.
Who is behind Butler?
A team at the Institute of Applied Physics, TU Wien, in Vienna. Butler was built for our own research — working with AI without letting go of the data.
See Butler on your own work.
Bring a meeting, a document or a question you would ask ChatGPT today — we show you what Butler makes of it.