Couchbase vs Alopex DB

What Couchbase is

Couchbase Server is a distributed JSON document database. Couchbase Lite is an embedded JSON document database for mobile and edge devices.

How it works

Couchbase Server: SQL-like queries, caching, key-value access, full-text search, analytics, and event-driven processing all run on JSON documents.
Couchbase Lite: embedded in the app, it stores and queries data locally with SQL++, even without a network. With Sync Gateway and Couchbase Server, it syncs data between the cloud and devices.
Server vector indexes: there are three kinds: Hyperscale Vector, Composite Vector, and Search Vector.
Lite vector indexes: the index is trained to compute centroids that group the vectors. Training starts on the first vector search query.

Main features

Couchbase Lite runs vector search on the device and has hybrid search combined with full-text search. Distance is Euclidean, squared Euclidean, cosine, or dot product. It also syncs peer to peer between devices.

Limits

Vector search in Couchbase Lite is an Enterprise feature, used by installing a separately downloaded extension library.
A Couchbase Lite vector query run before the index is trained scans every vector.
Couchbase Lite lazy indexes are not updated automatically; the application decides when to update them.
Couchbase Server Search Vector indexes do not support Euclidean or squared Euclidean distance.

How it differs from Alopex DB

Both can run embedded and have vector search.

Alopex DB is an embedded database queried with SQL. Data lives in a single .alopex file, and table rows and vectors are updated in the same transaction. The source code is published under Apache-2.0.

We recommend Alopex DB at the center of the setup, with the same database and the same SQL on device and server. The quickstart is there too.

References

Why Couchbase?, Couchbase Lite, Couchbase Lite: Vector Search, Couchbase Lite: Install, Couchbase Server: Vectors and indexes