whichdb
vs

PoloDB vs redb

PoloDB: Embedded BSON document database for Rust with a MongoDB-like API and optional wire-protocol server. redb: Pure-Rust embedded key-value store: copy-on-write B-trees, ACID, and a stable file format.

key differences

  • PoloDB is primarily a document database; redb is key-value.
  • Only PoloDB has secondary indexes, json, compression, online schema changes.

choose polodb for

  • +Rust desktop and CLI apps needing local document storage
  • +Edge services wanting MongoDB-like semantics without a server
  • +Tests that stub MongoDB with an embedded store

best at · Embedded, Edge, Coordination

choose redb for

  • +Local persistence for Rust desktop and CLI apps
  • +Embedded metadata and index storage in Rust services
  • +Replacing sled or LMDB bindings in Rust code

best at · Embedded, Local-first, Metadata

PoloDBEmbedded BSON document database for Rust with a MongoDB-like API and optional wire-protocol server.
redbPure-Rust embedded key-value store: copy-on-write B-trees, ACID, and a stable file format.
overview
Primary model
Document
Key-Value
Also supports
–
–
Type
Embedded library
Embedded library
Status
Active
Active
Developer
PoloDB project (Vincent Chan)
Christopher Berner
First release
2020
2021
Latest version
5.3.0 (Jul 26, 2026)
4.4.0 (Oct 13, 2026)
License
Open source (permissive)Apache License 2.0
Open source (permissive)MIT or Apache License 2.0
Free tier
✓
✓
popularity
WhichDB Score
3.2
13.8
Rank
#443
#245
GitHub stars
1.2K
4.9K
Stack Overflow questions
–
–
scale & guarantees
Comfortable data size
Small (≤ 100 GB)
Small (≤ 100 GB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Full
Full
Consistency
Strong
Strong
Schema
Schemaless
Strict
Architecture
Embedded, Client server
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
MongoDB-like query API (subset)
Rust API
Client languages
Rust, Python
Rust, Python
Best for
Embedded, Edge, Coordination
Embedded, Local-first, Metadata
Add more to this comparisonNot sure either fits? Try smart match

PoloDB vs redb: FAQ

What is the difference between PoloDB and redb?

PoloDB: Embedded BSON document database for Rust with a MongoDB-like API and optional wire-protocol server. redb: Pure-Rust embedded key-value store: copy-on-write B-trees, ACID, and a stable file format. PoloDB is primarily a document database; redb is key-value. Only PoloDB has secondary indexes, json, compression, online schema changes.

When should I choose PoloDB over redb?

Choose PoloDB for rust desktop and CLI apps needing local document storage; edge services wanting MongoDB-like semantics without a server; and tests that stub MongoDB with an embedded store. Choose redb for local persistence for Rust desktop and CLI apps; embedded metadata and index storage in Rust services; and replacing sled or LMDB bindings in Rust code.

Is PoloDB or redb more popular?

redb ranks #245 on the WhichDB Score (13.8/100) and PoloDB ranks #443 (3.2/100). Popularity is not fit: check the requirements that matter for your project.

Are PoloDB and redb open source?

Yes. PoloDB is open source. License: Apache License 2.0. Yes. redb is open source. License: MIT or Apache License 2.0.