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KurrentDB (EventStoreDB) vs XTDB

KurrentDB (EventStoreDB): A purpose-built event store for event sourcing, with streams, subscriptions and projections. XTDB: Bitemporal SQL database on object storage that keeps every version of every row.

key differences

  • KurrentDB (EventStoreDB) is primarily an event store database; XTDB is relational.
  • Licensing: KurrentDB (EventStoreDB) is source-available (Kurrent License v1 (KLv1)); XTDB is open source (copyleft) (Mozilla Public License 2.0).
  • Horizontal scaling is none in KurrentDB (EventStoreDB) and manual in XTDB.
  • Transactions: KurrentDB (EventStoreDB) offers limited ACID; XTDB offers full.
  • Only KurrentDB (EventStoreDB) has change data capture, pub/sub, encryption at rest, role-based access, streaming ingest.
  • Only XTDB has joins, columnar storage, compression.

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

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

KurrentDB (EventStoreDB)A purpose-built event store for event sourcing, with streams, subscriptions and projections.
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
Kurrent, Inc.
JUXT Ltd
First release
2012
2019
Latest version
26.2.3 (Oct 19, 2026)
2.2.0 (Oct 21, 2026)
License
Source-availableKurrent License v1 (KLv1)
Open source (copyleft)Mozilla Public License 2.0
Free tier
✓
✓
popularity
WhichDB Score
18.6
8.3
Rank
#177
#328
GitHub stars
5.9K
3.1K
Stack Overflow questions
185
7
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
None
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
Stream reads/subscriptions API, JavaScript projections, SQL (Arrow Flight)
SQL, XTQL
Client languages
C#, Java, JavaScript, Go, Python, Rust
Java, Kotlin, Clojure, Python, JavaScript, Go
Best for
Event sourcing, OLTP, Pub/Sub, Streaming
OLTP, Event sourcing, Ledger, HTAP
Add more to this comparisonNot sure either fits? Try smart match

KurrentDB (EventStoreDB) vs XTDB: FAQ

What is the difference between KurrentDB (EventStoreDB) and XTDB?

KurrentDB (EventStoreDB): A purpose-built event store for event sourcing, with streams, subscriptions and projections. XTDB: Bitemporal SQL database on object storage that keeps every version of every row. KurrentDB (EventStoreDB) is primarily an event store database; XTDB is relational. Licensing: KurrentDB (EventStoreDB) is source-available (Kurrent License v1 (KLv1)); XTDB is open source (copyleft) (Mozilla Public License 2.0). Horizontal scaling is none in KurrentDB (EventStoreDB) and manual in XTDB.

When should I choose KurrentDB (EventStoreDB) over XTDB?

Choose KurrentDB (EventStoreDB) for event-sourced domain models with CQRS; audit-heavy financial and logistics systems; and integrating microservices via durable event streams. 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 KurrentDB (EventStoreDB) or XTDB more popular?

KurrentDB (EventStoreDB) ranks #177 on the WhichDB Score (18.6/100) and XTDB ranks #328 (8.3/100). Popularity is not fit: check the requirements that matter for your project.

Are KurrentDB (EventStoreDB) and XTDB open source?

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). Yes. XTDB is open source. License: Mozilla Public License 2.0.