LMDB

6.7easy start · #17 of 31
in Embedded Databases

Free to practise onnot on record
Free trialnot on record
Well documentedyes
Runs where you workyes

Runs on Linux, Mac, self-hosted, Web, Windows.

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LMDB is ranked #17 of 31 in embedded databases on The Geeks Club. It runs on Linux, macOS, Self-hosted, Web, Windows.

LMDB plans and pricing

All plans

Enterprise Not published fixed-price source-level support · LMDB organizations symas.com · 1 Oct 2026

Gold Not published fixed-price source-level support · LMDB organizations symas.com · 1 Oct 2026

Compared on embedded databases

Free plan: Yes
Supported platforms: Windows and POSIX-compatible systems, including Linux and macOS
Database model: key-value
Query interface: nosql
Encryption: Yes
Data synchronization: No

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The record

Purpose: LMDB is an ultra-fast, ultra-compact, crash-proof key-value embedded data store developed for the OpenLDAP Project.
Persistence: Memory-mapped files provide read performance comparable to an in-memory database while retaining disk persistence.
Code size: LMDB is about 32KB of object code.
Transactions: LMDB provides full ACID semantics with MVCC, reader/writer transactions, and deadlock-free serialized writes.
Concurrency: Readers do not block writers, writers do not block readers, and multiple processes can open the same environment on one host.
Zero-copy access: LMDB uses memory-mapped files for zero-copy lookup and iteration and uses the operating system buffer cache.
Maintenance: LMDB requires no external process, background cleanup, compaction, application-level cache, logs, or crash-recovery procedure.
Data model: Keys are always sorted, making range lookups straightforward and efficient.
Sub-databases: LMDB supports multiple sub-databases with transactions covering all sub-databases in an environment.
Source availability: Development occurs in the OpenLDAP Project git repository and a clone is available on GitHub.
Integrations: Symas reports integrations with OpenDKIM, Heimdal Kerberos, Postfix, Cyrus SASL, MemcacheDB, SQLite3, and Riak.
Language support: Symas reports support for C, C++, Perl, Python, PHP, and other programming languages.
Utilities: LMDB includes mdb_stat for database status, mdb_copy for complete backups, and complete API documentation.
License: Symas states that LMDB is part of OpenLDAP and is under the OpenLDAP license, basically a BSD-style license.

Where it ranks on The Geeks Club

Best Embedded Databases in 2026#17 of 31

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Sources

symas.com/lmdb.php· checked 1 Oct 2026
symas.com/post.php· checked 1 Oct 2026