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LMDB vs WiredTiger

LMDB: Tiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026. WiredTiger: MongoDB's default storage engine: MVCC B-tree with compression and snapshot isolation.

key differences

  • Licensing: LMDB is open source (permissive) (OpenLDAP Public License 2.8); WiredTiger is open source (copyleft) (GNU GPL v2 or v3, or MongoDB commercial license).
  • Only WiredTiger has columnar storage, compression, encryption at rest, time travel.

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

choose wiredtiger for

  • +Storage engine inside MongoDB
  • +Embedding a transactional engine in a custom C system
  • +Research on MVCC B-tree storage

best at · Embedded, OLTP

LMDBTiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026.
WiredTigerMongoDB's default storage engine: MVCC B-tree with compression and snapshot isolation.
overview
Primary model
Key-Value
Key-Value
Also supports
–
Columnar / OLAP
Type
Embedded library
Embedded library
Status
Active
Active
Developer
Symas Corporation / OpenLDAP Project
MongoDB Inc.
First release
2011
2010
Latest version
1.0.2 (Sep 8, 2026)
11.3.1 (Nov 15, 2024)
License
Open source (permissive)OpenLDAP Public License 2.8
Open source (copyleft)GNU GPL v2 or v3, or MongoDB commercial license
Free tier
✓
✓
popularity
WhichDB Score
39.7
20.6
Rank
#47
#155
GitHub stars
3.1K
2.4K
Stack Overflow questions
260
170
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
None
None
Multi-region
None
None
ACID
Full
Full
Consistency
Strong
Strong
Schema
Schemaless
Schemaless
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
C API
C API
Client languages
C, C++, Python, Go, Rust, Java, JavaScript
C, Python, Java
Best for
Embedded, Metadata, Local-first
Embedded, OLTP
Add more to this comparisonNot sure either fits? Try smart match

LMDB vs WiredTiger: FAQ

What is the difference between LMDB and WiredTiger?

LMDB: Tiny memory-mapped B+tree with ACID transactions and lock-free readers; reached 1.0 in 2026. WiredTiger: MongoDB's default storage engine: MVCC B-tree with compression and snapshot isolation. Licensing: LMDB is open source (permissive) (OpenLDAP Public License 2.8); WiredTiger is open source (copyleft) (GNU GPL v2 or v3, or MongoDB commercial license). Only WiredTiger has columnar storage, compression, encryption at rest, time travel.

When should I choose LMDB over WiredTiger?

Choose LMDB for read-heavy embedded indexes and caches; directory services (OpenLDAP back-mdb); and blockchain and wallet state. Choose WiredTiger for storage engine inside MongoDB, embedding a transactional engine in a custom C system and research on MVCC B-tree storage.

Is LMDB or WiredTiger more popular?

LMDB ranks #47 on the WhichDB Score (39.7/100) and WiredTiger ranks #155 (20.6/100). Popularity is not fit: check the requirements that matter for your project.

Are LMDB and WiredTiger open source?

Yes. LMDB is open source. License: OpenLDAP Public License 2.8. Yes. WiredTiger is open source. License: GNU GPL v2 or v3, or MongoDB commercial license.