A high‑performance reasoner for the OWL 2 EL profile, tuned for very large taxonomies and incremental classification. It delivers fast computation of class hierarchies and consistency checks, which is valuable for low‑latency production pipelines. ELK is stable and integrates well with Protégé and server-side applications. It fully supports OWL2 EL, but does not provide complete OWL2 DL reasoning. SHACL/SPIN are handled by separate validators.