Edit your ontologies easier, faster and smarter!

Fluent Editor is free for individual developers, open source projects, academic research, education, and small professional teams.

W3C Standards



Custom plugins, custom grammars, R plugins, R package, Protege integration


Edit ontologies with Natural Language, quickly share and test instantly


Colaboratively edit ontologies within the team, connect directly to the server

Ontology Diagrams

Visually represent ontology within the diagram. With one click User may display an interactive diagram of the edited ontology. Moreover User may materialize the ontology (using selected materialization profile) and instantly inspect the results.

SWRL Debugger

SWRL is a powerful mechanism to build actual ontologies and express complex conditional relations for instances. Yet it is quite intractable to trace, especially for larger ontologies. To support users while modeling with SWRL we’ve delivered first version of embedded SWRL debugger. In a brief it allows to inspect which rules were executed during materialization and what entities was substituted for their head clauses (and used in the body).

Protégé interoperability

Protégé is a great tool for editing ontologies allowing deep insight into the structure of the OWL ontology. Fluent Editor allows user to focus on actual meaning of the ontology (taxonomy, vocabulary, rule set, etc) being edited. Those two tools can nicely collaborate. Now you can instantly synchronize view of the ontology between different windows of Fluent Editor and Protégé in one place. Just install the required plugin and the rest will be done with just one click – no matter which tool you are working with now.

R language package

R languageis widely used tool for statistical analysis. Combining ontologies and statistics opens an efficient way for quantitative-qualitative analysis of data. Now you can use both approaches conveniently in a single place by using an R language package to access ontologies (rOntorion). rOntorion R package allows direct access to ontologies created with Fluent Editor and opens them for semantic processing in R environment

Join 10,000+ industry and scientific users!

Fluent Editor, an ontology editor, is an Award Winning comprehensive tool for editing and manipulating complex ontologies that uses Controlled Natural Language. Fluent Editor provides one with a more suitable for human users alternative to XML-based OWL editors. It's main feature is the usage of Controlled English as a knowledge modeling language. Supported via Predictive Editor, it prohibits one from entering any sentence that is grammatically or morphologically incorrect and actively helps the user during sentence writing. The Controlled English is a subset of Standard English with restricted grammar and vocabulary in order to reduce the ambiguity and complexity inherent in full English.

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