European ChatGPT alternatives: Sluis ranked first

Verdict: For EU organisations, Sluis Workspace is the better choice because people sign in with Microsoft, Google or Apple and get chat, agents, Skills and Knowledge in one place, because EU-only routing and reversible pseudonymisation of personal data are enforced on every request, and because one usage-based bill (provider list price plus 10%, no seat fees) and one hash-chained audit trail replace a pile of licences and logs.

"ChatGPT alternative" can mean a place where employees chat with models, a platform where teams build agents, or a control layer in front of the models you already pay for. This page covers the first two, for organisations in the EU that need a defensible answer to "where does our data go, and who can see what happened". It is written by Sluis, so read our row as you would any vendor page. We checked every other row against the vendor's own documentation and list the sources at the end.

What we compared on

Marketing pages for employee AI tend to say "secure" and "GDPR compliant". Those words do not separate products. These criteria do:

Hosting and who operates it. Where the application runs, and which legal entity runs it.
Where model inference happens. Storage in the EU is not the same as inference in the EU. Ask for both.
Residency control. Can an administrator restrict where requests may go, and is that enforced or only documented?
Personal data in prompts. Does the product detect and remove personal data before a prompt reaches the model, or does it rely on employees to be careful?
Audit trail. What does an administrator or auditor get to look at after the fact?
Identity and administration. SSO, role separation, enterprise controls.
Certifications. Independent attestations the vendor itself publishes.
Price model. Per seat, per use, or custom quote.
Self-hosting. Whether you can run it on infrastructure you control.

The options at a glance

	Sluis Workspace	Mistral (Le Chat, now Vibe)	Langdock	Open WebUI (self-hosted)	ChatGPT Enterprise	Microsoft Copilot
Hosting	EU-hosted managed service run by 7Lab B.V., Amsterdam	EU by default, US endpoint optional	Multi-tenant on Microsoft Azure inside the EU	Your own infrastructure	OpenAI, with EU at-rest option for new workspaces	Microsoft 365 tenant, EU Data Boundary
Inference location	EU-only by default, refused before dispatch otherwise	Mistral models served from the EU by default; some features can transfer data out	Most models hosted in the EU, configurable	Whatever model you connect	In-region GPU inference for eligible Enterprise customers	EU traffic stays in the boundary, except Anthropic models
Residency enforcement	Organisation policy enforced per request, with audit entry for changes	Enterprise can switch off some out-of-EU features	Configurable per workspace	You build it	Set at workspace creation	Tenant and licence based
PII removal before the model	Detection and reversible pseudonymisation before dispatch	Not documented as a built-in step in the sources we checked	Not documented as a built-in step in the sources we checked	Not built in as a policy layer	Not documented as a built-in step in the sources we checked	Purview controls, content filters
Sign-in and SSO	Microsoft (Entra ID), Google, Apple; passkeys and authenticator app; SAML and SCIM on request (enterprise)	SAML SSO on Enterprise	SSO, SCIM and SAML on Business	You configure it	SAML SSO and SCIM	Entra ID
Audit	Hash-chained ledger, verifiable offline, grouped per request	Audit logs listed on Team and Enterprise	Governance add-on (free until 1 January 2027)	You build it	Not assessed here	Not assessed here
Certifications published	ISO 27001 certified	SOC 2 Type II, ISO 27001/27701	ISO 27001, SOC 2 Type II	None (a software project)	SOC 2 Type 2, ISO 27001, CSA STAR	ISO 27001, ISO 42001 and others
Price model	Provider list price plus 10%, no seat fee, prepaid from EUR 25	Free, Pro and Team per seat, Enterprise custom	Per seat (Business EUR 25), enterprise custom	Free to use, enterprise licence optional	Per seat, quote	Per-user add-on to Microsoft 365 (US$30)
Self-host	Optional enterprise data plane (Sluis Edge)	Enterprise deployments	Single tenant from 2,000 seats; own cloud and on-premise from 5,000	Yes	No	No
Best for	EU organisations: Sluis	One-vendor EU model stack	Seat-priced workflow rollout	Teams with a platform group	Teams that want the ChatGPT product	Microsoft 365 estates

1. Sluis Workspace

Sluis Workspace is the employee-facing half of Sluis. Everyone signs in with Microsoft, Google or Apple and lands in one workspace for chat, agents, Skills and Knowledge. There are no seat licences to manage. It sits behind the same gate as the Sluis gateway, so a Workspace message and an API call are inspected, routed and logged by one policy. Details are on the Sluis Workspace page.

Ease of use. You build an agent by describing it in a chat. Skills are versioned and can be published to the organisation, Knowledge can be private or shared, and spreadsheets and presentations go in and come out. The same workspace is available in the browser, with apps for macOS, Windows, Linux, iOS and Android on the download page.

Clarity. One policy covers chat, API traffic and coding agents. The console shows one audit row per request with its checks grouped underneath, plus workloads, budgets and a spend overview. The bill is one usage-based line: provider list price plus 10%, with no seat fee and no platform subscription.

Data security.

Residency is policy, not a promise. The default allows the EU jurisdiction only. A request that would reach a provider outside the allowed set is refused with a 403 before it is sent, so OpenAI models, for example, stay blocked until an owner allows the US jurisdiction with a recorded transfer-terms acknowledgement. EU ownership of the provider is a separate, stricter setting.
Personal data. Sensitive values are detected and reversibly pseudonymised before dispatch, and the «TOKEN» placeholders are restored on the way back. A hash-chained audit ledger records which policy ran, and you can verify the chain offline.
ISO 27001 certified, run by Sluis by SevenLab, legal entity 7Lab B.V. in Amsterdam, with Sluis Edge available for self-hosting on an enterprise contract.

Workspace functionality. Agent memory, scheduled agents, sub-agents, a house style, a reasoning level per chat, image generation, MCP tools and several model providers in one place, all on a gateway built in Rust.

Sign-in and administration. Sluis offers SSO with Microsoft Entra ID, Google and Apple, plus authenticator-app or passkey two-factor that owners can require. SAML and SCIM are available for enterprise contracts on request.

What to weigh: detection is not perfect, and using Sluis does not by itself establish GDPR or HIPAA compliance. Agent Harness traffic (the governed route for local coding agents) is the residency exception, because the provider subscription chooses the serving region and Sluis records it as unverified. Self-service has no free tier and starts with at least EUR 25 of prepaid credit. The desktop apps are alpha builds.

If you also want to govern API traffic and coding agents with the same policy, see AI gateways for EU organisations compared.

2. Mistral Le Chat (now Vibe)

Mistral is a French model provider with its own assistant. Its help centre states that data is hosted in the European Union by default, and that you can explicitly use a US API endpoint, in which case data is hosted in the United States. It also says that, depending on the feature, data can be temporarily transferred outside the EU to the subprocessors listed in its trust centre, under Standard Contractual Clauses, and that Enterprise customers can deactivate some of those features at organisation level. Mistral says it complies with SOC 2 Type II and ISO 27001/27701 frameworks.

It suits a one-vendor model stack from an EU-headquartered provider. See the detailed Sluis versus Mistral Le Chat comparison.

3. Langdock

Langdock is a German platform for rolling out AI to employees: chat, custom agents, workflows and an API. Its security page lists ISO 27001 certification and a SOC 2 Type II audit, no training on customer data, and a multi-tenant deployment hosted on Microsoft Azure inside the EU. The application and most models are hosted in the EU, and the model choice is configurable. Single-tenant SaaS starts at 2,000 seats, and bring-your-own-cloud and on-premise deployments at 5,000 seats. The Business plan, listed for up to 1,000 users, includes SSO, SCIM and SAML.

See the Sluis versus Langdock comparison.

4. Self-hosted options: Open WebUI and friends

Running an open interface on your own servers is the most direct answer to "where does the data go". Open WebUI is one example, and it pairs with any model backend you connect, including models you host yourself.

Two caveats. First, you take on the operations: updates, authentication, logging, retention, backup, and the work of building any policy layer. Second, the licence changed. The project's documentation states that code up to and including v0.6.5 is BSD-3-Clause, and that from v0.6.6 (April 2025) a branding clause applies: you may not remove or alter the Open WebUI branding unless you have 50 or fewer users in a 30-day period, have written permission, or hold an enterprise licence. The project says this is not an OSI-approved open source licence. Internal use at any scale is allowed with branding intact.

5. ChatGPT Enterprise

OpenAI offers data residency in Europe for ChatGPT Enterprise and Edu. New workspaces can store customer content at rest in the region, including conversations, uploaded files and custom GPTs. Eligible customers with residency enabled can add inference residency, which keeps GPU inference on in-scope content in Europe, the US or the UAE. OpenAI lists SOC 2 Type 2, ISO 27001 and CSA STAR among its certifications, documents SAML SSO and SCIM, publishes a DPA, and states that business-plan data is not used for training by default.

Residency applies to new workspaces, covers the data types OpenAI lists, and depends on your contract. It is a single-vendor model menu, and OpenAI is a US company, which matters if your legal analysis includes foreign-jurisdiction access to data. See the Sluis versus ChatGPT Enterprise comparison.

6. Microsoft Copilot

Copilot works on your existing Microsoft 365 permissions and content. Microsoft states that Copilot is an EU Data Boundary service, that EU traffic stays within the boundary, that prompts and responses are not used to train foundation models, and that it holds ISO 27001, ISO 42001 and other certifications. Two details deserve attention: models provided by Anthropic as a subprocessor are currently excluded from the EU Data Boundary, and Microsoft says LLM calls can go to other regions during high utilisation, with the EU Data Boundary safeguards applying to EU users. Copilot is sold as a US$30 per user per month add-on to a qualifying Microsoft 365 licence.

See the Sluis versus Microsoft 365 Copilot comparison. Anthropic's and Google's equivalents are covered in Sluis versus Claude for Work and Sluis versus Gemini for Workspace.

How to choose

You need one enforced policy across employee chat, API traffic and coding agents, easy sign-in, an audit trail you can verify offline, and usage-based pricing: Sluis.
You want assistance inside the Office apps above all: Copilot.
Your people want the ChatGPT product and your contract covers EU residency: ChatGPT Enterprise.
You want an EU-headquartered model vendor with its own assistant: Mistral.
You want a seat-priced, EU-operated workspace with workflow tooling: Langdock.
You have a platform team and will build governance yourself: Open WebUI or a similar interface.

Who might still pick the others

Microsoft Copilot, if most of the work happens inside Word, Excel and Outlook.
ChatGPT Enterprise, if you need OpenAI's product features and your contract already covers residency.
Mistral, if an EU model vendor is itself a requirement.
A self-hosted interface, if no managed service is acceptable to your security team (or Sluis Edge on an enterprise contract).

Our verdict

Sluis Workspace is the better choice for EU organisations: one sign-in with Microsoft, Google or Apple, one workspace for chat, agents, Skills and Knowledge, EU-only routing and pseudonymisation enforced per request, a verifiable audit trail, and one usage-based bill with no seats. See Sluis Workspace and pricing.

FAQ

What is the best European alternative to ChatGPT for a company?

For EU organisations we rank Sluis Workspace first: enforced EU-only routing, reversible pseudonymisation of personal data before dispatch, a hash-chained audit log, and an agent workspace with no seat licences. Mistral Le Chat and Langdock are EU-operated alternatives and Open WebUI is the self-hosted route. Verify every vendor's answers in writing.

Does EU data residency mean the model runs in the EU?

Not necessarily. Storage at rest and inference location are separate commitments, and some products route a subset of models or features outside the EU. Sluis refuses requests to providers outside the allowed jurisdictions before they are sent. Ask every vendor for both commitments in writing.

Can we self-host an employee AI workspace?

Yes. Open WebUI is the common choice, with the branding conditions described above. Langdock offers on-premise deployment from 5,000 seats, and Sluis offers Sluis Edge, an enterprise self-hosted data plane. Self-hosting the interface does not by itself control where the model runs, so check the model side too.

How does Sluis Workspace pricing compare with per-seat tools?

Sluis charges the provider's list price plus 10% for managed models, with no seat fee and no subscription, requires prepaid credit of at least EUR 25, and adds payment-method surcharges. You pay for what is used, so occasional users and agents cost nothing extra. Per-seat tools can be cheaper per head for heavy, uniform use.

Is Sluis certified?

Sluis is ISO 27001 certified. It does not claim GDPR or HIPAA compliance as a property of the product: its documentation says that using Sluis does not by itself establish either, and that personal-data detection is not perfect.