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Axon Server vs KurrentDB (EventStoreDB)

Axon Server: AxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps. KurrentDB (EventStoreDB): A purpose-built event store for event sourcing, with streams, subscriptions and projections.

key differences

  • Licensing: Axon Server is proprietary (AxonIQ subscription terms (connectors Apache-2.0)); KurrentDB (EventStoreDB) is source-available (Kurrent License v1 (KLv1)).
  • Horizontal scaling is native in Axon Server and none in KurrentDB (EventStoreDB).
  • Only KurrentDB (EventStoreDB) has json, change data capture, encryption at rest, time travel.

choose axon-server for

  • +CQRS and event-sourced Java microservices
  • +Replacing a broker plus event store in Axon-based systems

best at · Event sourcing, Pub/Sub, Queue

choose kurrentdb for

  • +Event-sourced domain models with CQRS
  • +Audit-heavy financial and logistics systems
  • +Integrating microservices via durable event streams

best at · Event sourcing, OLTP, Pub/Sub

Axon ServerAxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps.
KurrentDB (EventStoreDB)A purpose-built event store for event sourcing, with streams, subscriptions and projections.
overview
Primary model
Event Store
Event Store
Also supports
–
–
Type
Database engine
Database engine
Status
Active
Active
Developer
AxonIQ
Kurrent, Inc.
First release
2018
2012
Latest version
2026.1.7 (Oct 15, 2026)
26.2.3 (Oct 19, 2026)
License
ProprietaryAxonIQ subscription terms (connectors Apache-2.0)
Source-availableKurrent License v1 (KLv1)
Free tier
✓
✓
popularity
WhichDB Score
7.5
18.6
Rank
#342
#177
GitHub stars
–
5.9K
Stack Overflow questions
621
185
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
Native
None
Multi-region
Read replicas
Read replicas
ACID
Limited
Limited
Consistency
Strong
Strong
Schema
Schemaless
Schemaless
Architecture
Single node, Distributed, Client server
Single node, Distributed, Client server
deployment
Self-hosted
✓
✓
Vendor-managed cloud
✓
✓
Serverless
—
—
Embedded
—
—
Edge
—
—
Clouds
AWS, Google Cloud, Azure
AWS, Google Cloud, Azure
capabilities
Transactions
✓
✓
Joins
—
—
Secondary indexes
—
—
Full-text search
—
—
Vector search
—
—
Geospatial
—
—
JSON
—
✓
Change data capture
—
✓
Triggers
—
—
Stored procedures
—
—
Materialized views
—
—
TTL / expiry
—
—
Pub/Sub
✓
✓
Columnar storage
—
—
In-memory
—
—
Durable persistence
✓
✓
Compression
—
—
Encryption at rest
—
✓
Role-based access
✓
✓
Time travel
—
✓
Branching
—
—
Online schema changes
—
—
Streaming ingest
✓
✓
Offline sync
—
—
Runs in WebAssembly
—
—
interfaces
Query languages
Axon Framework API, Axon Server query language (events)
Stream reads/subscriptions API, JavaScript projections, SQL (Arrow Flight)
Client languages
Java, Kotlin
C#, Java, JavaScript, Go, Python, Rust
Best for
Event sourcing, Pub/Sub, Queue
Event sourcing, OLTP, Pub/Sub, Streaming
Add more to this comparisonNot sure either fits? Try smart match

Axon Server vs KurrentDB (EventStoreDB): FAQ

What is the difference between Axon Server and KurrentDB (EventStoreDB)?

Axon Server: AxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps. KurrentDB (EventStoreDB): A purpose-built event store for event sourcing, with streams, subscriptions and projections. Licensing: Axon Server is proprietary (AxonIQ subscription terms (connectors Apache-2.0)); KurrentDB (EventStoreDB) is source-available (Kurrent License v1 (KLv1)). Horizontal scaling is native in Axon Server and none in KurrentDB (EventStoreDB). Only KurrentDB (EventStoreDB) has json, change data capture, encryption at rest, time travel.

When should I choose Axon Server over KurrentDB (EventStoreDB)?

Choose Axon Server for CQRS and event-sourced Java microservices; and replacing a broker plus event store in Axon-based systems. Choose KurrentDB (EventStoreDB) for event-sourced domain models with CQRS; audit-heavy financial and logistics systems; and integrating microservices via durable event streams.

Is Axon Server or KurrentDB (EventStoreDB) more popular?

KurrentDB (EventStoreDB) ranks #177 on the WhichDB Score (18.6/100) and Axon Server ranks #342 (7.5/100). Popularity is not fit: check the requirements that matter for your project.

Are Axon Server and KurrentDB (EventStoreDB) open source?

No. Axon Server is proprietary, closed-source software. License: AxonIQ subscription terms (connectors Apache-2.0). Not in the OSI sense. KurrentDB (EventStoreDB) is source-available: you can read the code, but the license restricts some uses, typically offering it as a competing managed service. License: Kurrent License v1 (KLv1).