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Ontotext AD
TypePrivate corporation

Semantic Web
Semantic technology
Linked Data
Text mining
Information discovery
Graph database
Knowledge Engineering Triplestore

Knowledge Graph
Key people
Atanas Kiryakov, CEO

Vassil Momtchev, CTO

Veska Davidova, COO
ProductsOntotext GraphDB,[1]

Ontotext Semantic Platform, GraphDB Cloud,[2] Media & Publishing, Marketing Intelligence, Life Sciences & Healthcare, Compliance & Document Management,

Galleries, Libraries, Archives & Museums (GLAM)
WebsiteOntotext web site

Ontotext is a software company with offices in Europe and USA. It is the semantic technology branch of Sirma Group. Its main domain of activity is the development of software based on the Semantic Web languages and standards, in particular RDF, OWL and SPARQL. Ontotext is best known for the Ontotext GraphDB semantic graph database engine. Another major business line is the development of enterprise knowledge management and analytics systems that involve big knowledge graphs. Those systems are developed on top of the Ontotext Platform that builds on top of GraphDB capabilities for text mining using big knowledge graphs.

Together with BBC, Ontotext developed one of the early large-scale industrial semantic applications, Dynamic Semantic Publishing, starting in 2010.[3]

Ontotext content management systems deliver semantic tagging, classification, recommendation, search and discovery services. Typically they involve semantic data integration that results in a big knowledge graph, which combines proprietary master data with open data and commercially available datasets. These big knowledge graphs are used to provide context about the corresponding domain and semantic profiles of the key concepts and entities in it.


  • Ontotext GraphDB (formerly OWLIM) – a RDF triplestore available in three versions – Free, Standard and Enterprise. GraphDB is optimized for metadata and master data management, graph analytics and data publishing. Since version 8.0 GraphDB integrates OpenRefine to allow for easy ingestion and reconciliation of tabular data[4]
  • Ontotext Platform – providing an enrichment suite for text mining and semantic annotation, data integration tools that can transform data into RDF, and tools for semantic curation allowing users to search the knowledge base and curate content at the same time.[5]


Ontotext runs several public demonstration services:

  • NOW[6]News On the Web shows how a news feed can be categorized and enriched, implementing semantic faceted search. It demonstrates the capabilities of semantic technology for publishing purposes
  • Rank[7] – news popularity ranking of companies. Supports rankings by industry sectors and countries, including subsidiaries. Based on semantic tags that link news articles to big knowledge graph of linked open data
  • Fact Forge[8] – hub for open Linked data and news about people, organizations and locations. It includes more than 1 billion facts from popular datasets such as DBpedia, Geonames, Wordnet, the Panama Papers, etc., as well as ontologies such as the Financial Industry Business Ontology (FIBO)
  • Linked Life Data[9] – a data-as-a-service platform that provides access to 25 public biomedical databases through a single access point. The service allows writing of complex data analytical queries and answering complex bioinformatics questions. Simply navigate through the information, or export subsets such as 'all approved drugs and their brand names'
  • Linked Leaks[10]Panama Papers leak linked to additional knowledge about the world
  • Elections[11] – tracking of detailed behaviors in Bulgarian elections, e.g., indicating possible election irregularities

Open source software[edit]

Ontotext has supported the development of the following open source software, starting with EC research projects since 2001:

Research projects[edit]

The company has been involved in over 30 research projects in the European Commission Framework Programmes in the domains of Semantic Web, Linked Data, Open Data and Text mining.[14][15] An interactive project timeline is available.[16]


  1. ^ "Ontotext GraphDB". Ontotext.
  2. ^ "GraphDB Cloud". Ontotext.
  3. ^ O'Donovan, John. "The World Cup and a call to action around Linked Data". BBC Internet Blog. Retrieved 2 November 2016.
  4. ^ Howard, Philip (10 May 2017). "Graph update: Ontotext GraphDB". Bloor Research.
  5. ^ "Ontotext Metadata Studio". Ontotext. Retrieved 26 November 2022.
  6. ^ "NOW – News on the Web". Ontotext.
  7. ^ "Rank". Ontotext.
  8. ^ "FactForge". Ontotext.
  9. ^ "Linked Life Data". Ontotext.
  10. ^ "Linked Leaks". Ontotext.
  11. ^ "5-Star Linked Open Elections Data". Ontotext. 24 March 2021. Retrieved 11 April 2021.
  12. ^ "On-to-Knowledge Project Partners". STI2. Retrieved 2 November 2016.
  13. ^ "Developing Language Processing Components with GATE Version 8 (a User Guide)". University of Sheffield, Department of Computer Science 2001–2015. Retrieved 2 November 2016.
  14. ^ "CORDIS Project Search for "Ontotext" or "Sirma AI"". European Commission. Retrieved 27 January 2021.
  15. ^ "CORDIS Organization Profile: Ontotext". European Commission. Retrieved 27 January 2021.
  16. ^ "Ontotext Research Projects: Interactive Timeline". Ontotext. Retrieved 27 January 2021.