EU Sovereignty Score
Self-hosted / open sourceData Governance & MDMHeadquarters: FR

Opentheso: sovereignty score and 8 European alternatives

Opentheso is a web application for managing multilingual, multi-hierarchical thesauri. It follows the ISO 25964-1 and ISO 25964-2 standards and is used by research teams, libraries and heritage institutions that build and share vocabularies and classification schemes. Features include drag-and-drop management of concepts and branches, collaborative work with four permission levels, automatic generation of ARK and Handle identifiers, REST, OpenAPI and GraphQL web services, and import and export in SKOS, Turtle, JSON-LD and CSV. You install the software yourself on a server, for example on Debian or Ubuntu or with Docker.

Opentheso was originally developed for Frantiq, a CNRS service group, at the Maison de l'Orient et de la Méditerranée (MOM) in France. Its further development is supported by the MOM, the Huma-Num consortium and the Frantiq network. It is released under CeCILL-C, a French free-software licence that is compatible with the GNU GPL. Because you run Opentheso on your own infrastructure, your vocabularies and data stay under your own control. A shared instance for research projects is also available via Huma-Num.

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Sovereignty score
71 / 1000 = high exposure
100 = sovereign
  • Jurisdiction SOV-2100
    Headquartered in the EU: European law applies
  • Data residency SOV-3100
    EU-only hosting
  • Cryptographic key sovereignty SOV-360
    Key management with a European vendor
  • Freedom from lock-in SOV-640
    Closed source: switching requires data migration
  • Source & runtime sovereignty SOV-4 · SOV-655
    Closed source, runtime with the vendor

SOV codes: the matching objective in the European Commission's Cloud Sovereignty Framework. Official source

How the score is calculated

Facts and evidence

Last checked October 14, 2026
Headquarters
FR (EU)Verified by hand
Sovereignty model
Open-source, distributedVerified by hand
Data hosting
EUVerified by hand
Open-source
NoVerified by hand
GDPR-compliant
YesVendor-stated
Category
Data Governance & MDM
Type
Product
Website
opentheso.huma-num.fr ↗

How we verify · Something wrong? Suggest a correction

Top EU-based & GDPR-compliant alternatives to Opentheso

The European alternatives to Opentheso come from our knowledge base of over 8,400 vendors. We only list vendors headquartered in the EU or the EEA; fully European-owned vendors rank before vendors with a foreign owner. For each alternative you see the country, the open-source status and a short description.

Score per alternative: 0 = high exposure, 100 = sovereign

28 European Data Governance & MDM vendors are in the catalogue. View the whole category · Submit an alternative · View category on the map

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Why digital sovereignty matters with Opentheso

Opentheso is headquartered in FR and therefore falls under European law: the GDPR, NIS2 and the Data Act. No foreign legislation can compel access to your data.

Data is hosted exclusively in the EU, so Opentheso scores best on data residency.

Opentheso is closed source and hosted by the vendor. The encryption keys and the runtime sit with the vendor and switching requires data migration. Ask about bring-your-own-key, export options and open standards.

What this means for your organisation depends on your whole stack and context. The free assessment weighs Opentheso together with your other vendors and gives a total score, a heatmap and the main risk drivers.

Frequently asked questions

What is the best European alternative to Opentheso?

It depends on your use case. Strong EU alternatives to Opentheso include Accutics, Amnesia and Anjana Data. On this page you can compare 8 EU alternatives by jurisdiction, data residency and open-source status.

Are there open-source alternatives to Opentheso?

Yes. Open-source EU alternatives to Opentheso include Amnesia, ARX Data Anonymization Tool and Data Contract CLI. These keep your data fully under your own control and let you self-host if you want to.

Is Opentheso GDPR-compliant and where is the data hosted?

Opentheso is headquartered in FR (EU) and hosts data in EU. That makes Opentheso an EU-sovereign choice in its own right; the EU alternatives on this page are comparable European tools.

Details and sources

Verified by handHeadquarters, owner, hosting locations and licence have been checked by us against public sources. Free of charge and for every vendor, not a paid label. Nothing in this knowledge base is taken over automatically. Last checked on October 14, 2026.

Sources

Public sources used in the latest check of this record.

Compliance evidence

The links below point to the vendor's own public documents. We only record what we found: a missing link means "not found publicly", not "not compliant".

No public compliance evidence has been recorded for this vendor yet. Do you know its DPA or subprocessor list? Something wrong? Suggest a correction

In the changelog

Earlier changes to this page, as listed in the public changelog.

Digital sovereignty in Data Governance & MDM

Data Governance & MDM: Data catalogues, lineage, data quality, ownership and master data management. In this category the choice of vendor determines who has legal access to your data, where that data lives and how easily you can switch later.

Also in this category

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8 European alternatives to Opentheso — GDPR-compliant & EU-hosted · EU Sovereignty Score