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eXtremeDB vs LMDB

eXtremeDB: Embedded in-memory and hybrid database for devices, real-time systems and time-series analytics. LMDB: Tiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026.

key differences

  • Licensing: eXtremeDB is proprietary (Commercial (per-product licensing)); LMDB is open source (permissive) (OpenLDAP Public License 2.8).
  • Horizontal scaling is native in eXtremeDB and none in LMDB.
  • Only eXtremeDB has joins, secondary indexes, vector search, geospatial, columnar storage.

choose extremedb for

  • +Embedded databases in network equipment
  • +Avionics and defence systems
  • +Industrial controllers and edge gateways
  • +In-process market data analytics

best at · Embedded, Edge, Time-series

choose lmdb for

  • +Read-heavy embedded indexes and caches
  • +Directory services (OpenLDAP back-mdb)
  • +Blockchain and wallet state
  • +ML dataset storage with fast random reads

best at · Embedded, Metadata, Local-first

eXtremeDBEmbedded in-memory and hybrid database for devices, real-time systems and time-series analytics.
LMDBTiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026.
overview
Primary model
Key-Value
Key-Value
Also supports
Relational, Time-Series, Columnar / OLAP, Vector
–
Type
Embedded library
Embedded library
Status
Active
Active
Developer
McObject
Symas Corporation / OpenLDAP Project
First release
2001
2011
Latest version
9.0 (Jul 15, 2026)
1.0.2 (Sep 8, 2026)
License
ProprietaryCommercial (per-product licensing)
Open source (permissive)OpenLDAP Public License 2.8
Free tier
—
✓
popularity
WhichDB Score
4.0
39.7
Rank
#421
#47
GitHub stars
–
3.1K
Stack Overflow questions
–
260
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
Native
None
Multi-region
None
None
ACID
Full
Full
Consistency
Strong
Strong
Schema
Strict
Schemaless
Architecture
Embedded, In memory, Client server, Distributed
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
SQL (eXtremeSQL), Native C/C++ API
C API
Client languages
C, C++, Java, Python, C#
C, C++, Python, Go, Rust, Java, JavaScript
Best for
Embedded, Edge, Time-series, Tick data
Embedded, Metadata, Local-first
Add more to this comparisonNot sure either fits? Try smart match

eXtremeDB vs LMDB: FAQ

What is the difference between eXtremeDB and LMDB?

eXtremeDB: Embedded in-memory and hybrid database for devices, real-time systems and time-series analytics. LMDB: Tiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026. Licensing: eXtremeDB is proprietary (Commercial (per-product licensing)); LMDB is open source (permissive) (OpenLDAP Public License 2.8). Horizontal scaling is native in eXtremeDB and none in LMDB. Only eXtremeDB has joins, secondary indexes, vector search, geospatial, columnar storage.

When should I choose eXtremeDB over LMDB?

Choose eXtremeDB for embedded databases in network equipment; avionics and defence systems; and industrial controllers and edge gateways. Choose LMDB for read-heavy embedded indexes and caches; directory services (OpenLDAP back-mdb); and blockchain and wallet state.

Is eXtremeDB or LMDB more popular?

LMDB ranks #47 on the WhichDB Score (39.7/100) and eXtremeDB ranks #421 (4.0/100). Popularity is not fit: check the requirements that matter for your project.

Are eXtremeDB and LMDB open source?

No. eXtremeDB is proprietary, closed-source software. License: Commercial (per-product licensing). Yes. LMDB is open source. License: OpenLDAP Public License 2.8.