whichdb
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ObjectBox vs WatermelonDB

ObjectBox: Fast on-device object database with built-in HNSW vector search and an optional commercial sync server. WatermelonDB: Lazy-loading reactive database for React Native and React apps, built on SQLite.

key differences

  • ObjectBox is primarily an object database; WatermelonDB is relational.
  • Licensing: ObjectBox is proprietary (Free closed-source core; Apache-2.0 language bindings); WatermelonDB is open source (permissive) (MIT License).
  • Transactions: ObjectBox offers full ACID; WatermelonDB offers limited.
  • Only ObjectBox has vector search, in-memory.

choose objectbox for

  • +Offline-first Android and Flutter apps
  • +On-device AI features needing local vector search
  • +IoT gateways and embedded Linux devices
  • +Replacing Realm after the Device Sync shutdown

best at · Embedded, Mobile/offline, IoT

choose watermelondb for

  • +Offline-capable React Native productivity apps
  • +Apps with large local lists that must render instantly
  • +Custom sync to an existing REST backend

best at · Mobile/offline, Local-first, Embedded

ObjectBoxFast on-device object database with built-in HNSW vector search and an optional commercial sync server.
WatermelonDBLazy-loading reactive database for React Native and React apps, built on SQLite.
overview
Primary model
Object
Relational
Also supports
Vector
–
Type
Embedded library
Embedded library
Status
Active
Active
Developer
ObjectBox Ltd.
Nozbe
First release
2017
2018
Latest version
Java 5.4.2 (May 6, 2026)
0.28.0 (Apr 7, 2025)
License
ProprietaryFree closed-source core; Apache-2.0 language bindings
Open source (permissive)MIT License
Free tier
✓
✓
popularity
WhichDB Score
12.4
17.8
Rank
#269
#187
GitHub stars
4.6K
11.8K
Stack Overflow questions
416
46
scale & guarantees
Comfortable data size
Small (≤ 100 GB)
Small (≤ 100 GB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Full
Limited
Consistency
Strong
Eventual
Schema
Strict
Strict
Architecture
Embedded
Embedded
deployment
Self-hosted
✓
✓
Vendor-managed cloud
—
—
Serverless
—
—
Embedded
✓
✓
Edge
✓
—
Clouds
–
–
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
ObjectBox Query Builder API
WatermelonDB Query API (Q)
Client languages
Java, Kotlin, Dart, Swift, C, C++, Go, Python
JavaScript, TypeScript
Best for
Embedded, Mobile/offline, IoT, Vector search
Mobile/offline, Local-first, Embedded
Add more to this comparisonNot sure either fits? Try smart match

ObjectBox vs WatermelonDB: FAQ

What is the difference between ObjectBox and WatermelonDB?

ObjectBox: Fast on-device object database with built-in HNSW vector search and an optional commercial sync server. WatermelonDB: Lazy-loading reactive database for React Native and React apps, built on SQLite. ObjectBox is primarily an object database; WatermelonDB is relational. Licensing: ObjectBox is proprietary (Free closed-source core; Apache-2.0 language bindings); WatermelonDB is open source (permissive) (MIT License). Transactions: ObjectBox offers full ACID; WatermelonDB offers limited.

When should I choose ObjectBox over WatermelonDB?

Choose ObjectBox for offline-first Android and Flutter apps; on-device AI features needing local vector search; and IoT gateways and embedded Linux devices. Choose WatermelonDB for offline-capable React Native productivity apps, apps with large local lists that must render instantly and custom sync to an existing REST backend.

Is ObjectBox or WatermelonDB more popular?

WatermelonDB ranks #187 on the WhichDB Score (17.8/100) and ObjectBox ranks #269 (12.4/100). Popularity is not fit: check the requirements that matter for your project.

Are ObjectBox and WatermelonDB open source?

No. ObjectBox is proprietary, closed-source software. License: Free closed-source core; Apache-2.0 language bindings. Yes. WatermelonDB is open source. License: MIT License.