GPL vs LGPL: Key Differences Developers Must Know
GPL (General Public License) requires derivative projects to adopt the same open-source license. LGPL (Lesser General Public License) relaxes that demand, allowing proprietary code to link dynamically to the library without forcing the entire project to become open-source.
Developers often confuse the two because both stem from the GNU project and share copyleft ideals. The difference feels subtle until you face a corporate legal review deciding if your closed-source app can safely use a popular C library.
Key Differences
GPL spreads its license to any combined work—static or dynamic linking triggers full open-sourcing. LGPL permits dynamic linking only; static linking or code modification still inherits LGPL, but the calling application remains proprietary.
Which One Should You Choose?
Choose GPL when you want every improvement shared, like Linux kernel drivers. Pick LGPL when you provide a utility library you want widespread adoption of, even in commercial software, such as FFmpeg or glibc.
Examples and Daily Life
WordPress themes must be GPL-compatible, so paid themes still share code. Meanwhile, closed-source Spotify on Linux uses LGPL libraries like PulseAudio without releasing the whole client.
Can I sell GPL software?
Yes, but you must provide source code and allow redistribution under GPL.
Does LGPL let me keep my app closed-source?
Yes, if you only dynamically link to the LGPL library and don’t modify it.
What happens if I accidentally mix GPL code into a proprietary app?
You must either open-source the entire app or remove the GPL component to comply.