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Datomic vs SirixDB

Datomic: Immutable Datalog database from Nubank where every fact is timestamped and queries run in the app process. SirixDB: Embeddable bitemporal database that keeps every revision of JSON and XML resources queryable.

key differences

  • Datomic is primarily a relational database; SirixDB is document.
  • Datomic is built for larger datasets (≤ 10 TB) than SirixDB (≤ 100 GB).
  • Only Datomic has joins, full-text search, change data capture.
  • Only SirixDB has json.

choose datomic for

  • +Financial and banking domain models needing auditability
  • +Systems that must answer what was known at a given time
  • +Complex domain graphs in Clojure services

best at · OLTP, Event sourcing, Ledger

choose sirixdb for

  • +Audit trails that must reconstruct any past state
  • +Versioned JSON or XML document storage
  • +Time-travel analytics over changing data
  • +Research and teaching on versioned storage engines

best at · Event sourcing, Content, Embedded

DatomicImmutable Datalog database from Nubank where every fact is timestamped and queries run in the app process.
SirixDBEmbeddable bitemporal database that keeps every revision of JSON and XML resources queryable.
overview
Primary model
Relational
Document
Also supports
Graph
XML
Type
Database engine
Database engine
Status
Active
Active
Developer
Nubank (Cognitect)
SirixDB open-source project (University of Konstanz origins)
First release
2012
2012
Latest version
1.0.7745 (Oct 16, 2026)
1.0.0-beta7 (Jul 15, 2026)
License
Open source (permissive)Apache-2.0 (binaries only; source not published)
Open source (permissive)BSD 3-Clause License
Free tier
✓
✓
popularity
WhichDB Score
14.9
6.0
Rank
#225
#370
GitHub stars
–
1.2K
Stack Overflow questions
436
–
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Small (≤ 100 GB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Full
Full
Consistency
Strong
Strong
Schema
Flexible
Schemaless
Architecture
Distributed, Shared storage
Embedded, Client server, Single node
deployment
Self-hosted
✓
✓
Vendor-managed cloud
—
—
Serverless
—
—
Embedded
✓
✓
Edge
—
—
Clouds
AWS
–
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
Datalog, Pull API
JSONiq, XQuery
Client languages
Clojure, Java
Java, Kotlin
Best for
OLTP, Event sourcing, Ledger, Knowledge graph
Event sourcing, Content, Embedded
Add more to this comparisonNot sure either fits? Try smart match

Datomic vs SirixDB: FAQ

What is the difference between Datomic and SirixDB?

Datomic: Immutable Datalog database from Nubank where every fact is timestamped and queries run in the app process. SirixDB: Embeddable bitemporal database that keeps every revision of JSON and XML resources queryable. Datomic is primarily a relational database; SirixDB is document. Datomic is built for larger datasets (≤ 10 TB) than SirixDB (≤ 100 GB). Only Datomic has joins, full-text search, change data capture.

When should I choose Datomic over SirixDB?

Choose Datomic for financial and banking domain models needing auditability; systems that must answer what was known at a given time; and complex domain graphs in Clojure services. Choose SirixDB for audit trails that must reconstruct any past state, versioned JSON or XML document storage and time-travel analytics over changing data.

Is Datomic or SirixDB more popular?

Datomic ranks #225 on the WhichDB Score (14.9/100) and SirixDB ranks #370 (6.0/100). Popularity is not fit: check the requirements that matter for your project.

Are Datomic and SirixDB open source?

Yes. Datomic is open source. License: Apache-2.0 (binaries only; source not published). Yes. SirixDB is open source. License: BSD 3-Clause License.