Ontop vs Stardog

Both are rdf databases queried with SPARQL. Ontop (2009, Apache-2.0, Java) ranks #18 this month; Stardog (2011, Proprietary, Java) ranks #23.

Attribute Ontop #18 ▲2 Strong Stardog #23 ▲10 Strong
At a glance
Rank #18#23
Score 57.055.7
GitHub stars 1k—
Popularity 58.453.2
Activity 49.463.1
Community 65.652.9
Research 54.850.2
Fundamentals
Description A Virtual Knowledge Graph system that exposes relational databases as RDF knowledge graphs, translating SPARQL queries into SQL without moving data. Uses R2RML mappings and lightweight ontologies.An RDF-based knowledge graph database with OWL 2 reasoning and property graph extensions. Includes Voicebox, an OpenAI-compatible natural language query interface via LLM integration.
Vendor OntopicStardog Union
Model RDFRDF
Kind query-enginedatabase
Category EstablishedEnterprise
First released 20092011
Status activeactive
License Apache-2.0Proprietary
Written in JavaJava
Query languages SPARQLSPARQL, SQL, GraphQL
gdotv support noyes

Feature scores — not surveyed for Ontop

Feature OntopStardog
Community & Business
Active development —0.5
Commercial support —✓
Live community —✓
Open Source —·
Pricing —·
Trendiness —✓
Deployment
Containerization —✓
Work as dedicated instance —✓
Work as embedded —·
Testing in-memory version —·
Platform
Operating on Linux —✓
Operating on Windows —·
SaaS offering —✓
Operations
Automatic updates —·
Client side caching —·
Data versioning support —·
Live backups —✓
Distribution
Cluster Re-balancing —·
Data Distribution —·
High-Availability —✓
Query Distribution —✓
Replication support —✓
Developer Experience
Data types defined —0.5
Logging/Auditing —✓
Object-Graph Mapper —·
Reactive programming —✓
Documentation up-to-date —✓
Binary protocol —·
CLI —✓
GUI —✓
Data Model
Multi-database —✓
Graph-native data —·
REST API —✓
Query Language —✓
Transactions
Granular locking —✓
Multiple isolation levels —✓
Read committed transaction —·
Transaction support —✓
Schema & Security
Constraints —✓
Schema support —✓
Secondary indexes —✓
Server side procedures —✓
Triggers —·
Authentication —✓
Authorization —✓
Data encryption —·