maxmind/libmaxminddb
FreeC library for the MaxMind DB file format
FreeFree tier
About maxmind/libmaxminddb
The libmaxminddb library provides a C library for reading MaxMind DB files, including the GeoIP databases from MaxMind. It implements a custom binary format designed for fast IP address lookups while supporting flexible data types associated with each address. The library is written in C99, compatible with POSIX.1-2001, and works with GCC 4.4+ and clang 3.2+. It is licensed under the Apache License, Version 2.0. The MaxMind DB format is an open format, with the specification available under Creative Commons Attribution-ShareAlike 3.0. Installation is supported via standard autotools (./configure, make, make install) or CMake.
Key Features
Provides a C library for reading MaxMind DB files (including GeoIP databases)
Custom binary format designed for fast IP address lookups
Allows flexible data types associated with each IP address
Supports C99 and POSIX.1-2001 standards
Compatible with GCC 4.4+ and clang 3.2+
Open format with a freely available specification
Licensed under Apache License, Version 2.0
Builds with autotools (./configure, make) or CMake
Pros & Cons
Pros
- Open source with Apache 2.0 license
- High-performance binary format optimized for fast lookups
- Well-documented and widely used (MaxMind GeoIP)
- Support for flexible data types (e.g., strings, maps, arrays)
- Portable: works on Linux, macOS, and other POSIX systems
- Stable library with a long history of development
Cons
- Limited to reading MaxMind DB format (not a general-purpose database)
- Requires C development environment and compilation skills
- No built-in IP range or subnet query support (only exact IP lookups)
- Documentation primarily technical; may have a learning curve for non-C developers
Best For
Reading MaxMind GeoIP databases for IP geolocationBuilding networking or security tools that require fast IP-to-location lookupsEmbedding IP geolocation capabilities into C applicationsAccessing and querying MaxMind DB files in a custom application