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Axon Server vs XTDB

Axon Server: AxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps. XTDB: Bitemporal SQL database on object storage that keeps every version of every row.

key differences

  • Axon Server is primarily an event store database; XTDB is relational.
  • Licensing: Axon Server is proprietary (AxonIQ subscription terms (connectors Apache-2.0)); XTDB is open source (copyleft) (Mozilla Public License 2.0).
  • Horizontal scaling is native in Axon Server and manual in XTDB.
  • Transactions: Axon Server offers limited ACID; XTDB offers full.
  • Only Axon Server has pub/sub, role-based access, streaming ingest.
  • Only XTDB has joins, json, columnar storage, compression, 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 xtdb for

  • +Financial and insurance systems needing as-of reporting
  • +Audit trails with retroactive corrections
  • +Event-sourced systems wanting SQL over history

best at · OLTP, Event sourcing, Ledger

Axon ServerAxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps.
XTDBBitemporal SQL database on object storage that keeps every version of every row.
overview
Primary model
Event Store
Relational
Also supports
–
Document, Columnar / OLAP
Type
Database engine
Database engine
Status
Active
Active
Developer
AxonIQ
JUXT Ltd
First release
2018
2019
Latest version
2026.1.7 (Oct 15, 2026)
2.2.0 (Oct 21, 2026)
License
ProprietaryAxonIQ subscription terms (connectors Apache-2.0)
Open source (copyleft)Mozilla Public License 2.0
Free tier
✓
✓
popularity
WhichDB Score
7.5
8.3
Rank
#342
#328
GitHub stars
–
3.1K
Stack Overflow questions
621
7
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
Native
Manual
Multi-region
Read replicas
None
ACID
Limited
Full
Consistency
Strong
Strong
Schema
Schemaless
Flexible
Architecture
Single node, Distributed, Client server
Distributed, Shared storage
deployment
Self-hosted
✓
✓
Vendor-managed cloud
✓
—
Serverless
—
—
Embedded
—
—
Edge
—
—
Clouds
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)
SQL, XTQL
Client languages
Java, Kotlin
Java, Kotlin, Clojure, Python, JavaScript, Go
Best for
Event sourcing, Pub/Sub, Queue
OLTP, Event sourcing, Ledger, HTAP
Add more to this comparisonNot sure either fits? Try smart match

Axon Server vs XTDB: FAQ

What is the difference between Axon Server and XTDB?

Axon Server: AxonIQ's event store and message router for Axon Framework CQRS and event-sourced apps. XTDB: Bitemporal SQL database on object storage that keeps every version of every row. Axon Server is primarily an event store database; XTDB is relational. Licensing: Axon Server is proprietary (AxonIQ subscription terms (connectors Apache-2.0)); XTDB is open source (copyleft) (Mozilla Public License 2.0). Horizontal scaling is native in Axon Server and manual in XTDB.

When should I choose Axon Server over XTDB?

Choose Axon Server for CQRS and event-sourced Java microservices; and replacing a broker plus event store in Axon-based systems. Choose XTDB for financial and insurance systems needing as-of reporting; audit trails with retroactive corrections; and event-sourced systems wanting SQL over history.

Is Axon Server or XTDB more popular?

XTDB ranks #328 on the WhichDB Score (8.3/100) and Axon Server ranks #342 (7.5/100). Popularity is not fit: check the requirements that matter for your project.

Are Axon Server and XTDB open source?

No. Axon Server is proprietary, closed-source software. License: AxonIQ subscription terms (connectors Apache-2.0). Yes. XTDB is open source. License: Mozilla Public License 2.0.