OpenLDES is an open-source reference implementation and tooling ecosystem for the Linked Data Event Streams (LDES) specification developed within SEMIC. It enables public administrations and other organisations to publish, access and synchronise data as immutable event streams using linked-data principles. 

Key characteristics include: 

• Reusable software components, libraries and deployment patterns implementing the LDES specification, embeddable in data platforms, data spaces and data-exchange infrastructures. 

• Core components include an LDES server and linked-data interaction components (such as the LDES Client and Apache NiFi components). 

• Supports near real-time data sharing, historical replication and efficient synchronisation of changes over time. 

• Designed for cross-border and cross-domain reuse, notably within European data spaces and open-data ecosystems. 

• Assessed under the CAMSS EIF scenario, achieving a "Seamless" compliance level (4020/4500). 

OpenLDES is released as open-source software; it originates from the Flanders Smart Data Space project, funded under the Recovery and Resilience Facility (NextGenerationEU), and is maintained and operated by the OpenLDES Community. 

It is released under the European Union Public Licence (EUPL 1.2).