whichdb
vs

SDB vs UnQLite

SDB: Tiny embeddable C string key-value database from the radare2 project, built on djb's cdb format. UnQLite: Embedded, transactional key-value and JSON document engine in a single C file, with Jx9 scripting.

key differences

  • Transactions: SDB offers limited ACID; UnQLite offers full.
  • Only UnQLite has transactions, online schema changes.

choose sdb for

  • +Embedded configuration and metadata storage in C programs
  • +Storing analysis state in reverse-engineering tools
  • +Lightweight persistent caches with a memcached front end

best at · Embedded, Coordination, Metadata

choose unqlite for

  • +Embedded devices and firmware needing local storage
  • +Desktop or game apps storing JSON state
  • +Local caches inside native services

best at · Embedded, IoT, Coordination

SDBTiny embeddable C string key-value database from the radare2 project, built on djb's cdb format.
UnQLiteEmbedded, transactional key-value and JSON document engine in a single C file, with Jx9 scripting.
overview
Primary model
Key-Value
Key-Value
Also supports
Document
Document
Type
Embedded library
Embedded library
Status
Active
Active
Developer
pancake and the radare2 project
Symisc Systems
First release
2012
2013
Latest version
2.5.8 (Oct 4, 2026)
1.2.1 (May 1, 2026)
License
Open source (permissive)MIT License
Open source (permissive)BSD 2-Clause
Free tier
✓
✓
popularity
WhichDB Score
1.6
4.1
Rank
#530
#419
GitHub stars
232
2.3K
Stack Overflow questions
–
–
scale & guarantees
Comfortable data size
Small (≤ 100 GB)
Small (≤ 100 GB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Limited
Full
Consistency
Strong
Strong
Schema
Schemaless
Schemaless
Architecture
Embedded, In memory
Embedded, In memory
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
sdb command syntax
Jx9, Key-value C API
Client languages
C, Vala, Node.js
C, C++, Python
Best for
Embedded, Coordination, Metadata
Embedded, IoT, Coordination, Edge
Add more to this comparisonNot sure either fits? Try smart match

SDB vs UnQLite: FAQ

What is the difference between SDB and UnQLite?

SDB: Tiny embeddable C string key-value database from the radare2 project, built on djb's cdb format. UnQLite: Embedded, transactional key-value and JSON document engine in a single C file, with Jx9 scripting. Transactions: SDB offers limited ACID; UnQLite offers full. Only UnQLite has transactions, online schema changes.

When should I choose SDB over UnQLite?

Choose SDB for embedded configuration and metadata storage in C programs; storing analysis state in reverse-engineering tools; and lightweight persistent caches with a memcached front end. Choose UnQLite for embedded devices and firmware needing local storage; desktop or game apps storing JSON state; and local caches inside native services.

Is SDB or UnQLite more popular?

UnQLite ranks #419 on the WhichDB Score (4.1/100) and SDB ranks #530 (1.6/100). Popularity is not fit: check the requirements that matter for your project.

Are SDB and UnQLite open source?

Yes. SDB is open source. License: MIT License. Yes. UnQLite is open source. License: BSD 2-Clause.