What library license best supports wide use while preventing proprietary forks?

[Donald.W]

I'm developing a software library I plan to release as open source, but I'm completely lost on choosing the right license. My goal is to allow widespread use in both personal and commercial projects, but I want to prevent a large company from taking the code, making proprietary modifications, and selling it without contributing back. I've been looking at the GPL, LGPL, and MIT licenses, but the nuances around linking and distribution are confusing. What are the practical implications of each for a library intended for use by other developers, not an end-user application?

[Sophia.G]

Here's the quick intuition: MIT is the simplest and most permissive; GPL (v3) enforces copyleft; LGPL is designed for libraries and allows linking with non-GPL apps (as long as you respect the terms). If your goal is to prevent a big company from taking your code and selling it as closed source, GPLv3 (or AGPL if you're worried about SaaS) provides real teeth; but it can complicate adoption by companies who don't want to open their downstream code. A common compromise is to use LGPL for a library, or a dual-license approach (MIT for most users, a separate GPL/enterprise license for those who want copyleft constraints).

[LunaA]

On practical differences: distribution vs linking; If your project is purely a library, LGPL is typically the standard for library use. If you're a standalone app, the GPL's copyleft kicks in heavily. For commercial use, MIT or Apache 2.0 are friendlier and patent-friendly (Apache 2.0).

[John.S]

A handy option some projects use is adding a linking exception: you can modify an MIT-style license to include a clause that explicitly allows linking with non-MPL/GPL code. Drafting that properly is tricky, so plan to have it reviewed.

[Scarlett_W]

Dual licensing approach: Provide code under MIT as default; offer GPLv3 as an alternate license for users who want copyleft; for enterprises, offer a commercial license if they want to keep their code closed. This is a proven pattern, but it means you’ll maintain multiple license texts and track who’s using what.

[Hannah27]

Practical steps to implement: 1) pick a base license, 2) include a LICENSE file in the repo and ensure every file has an attribution if required, 3) draft a short CONTRIBUTING guide that mentions licensing, 4) consider a contributor license agreement if you expect many external contributors, 5) prepare a simple README that explains how to choose between licenses, 6) set up a process for handling license questions and potential relicensing.

[Jonathan.G]

If you want, tell me your language/ecosystem and whether you’re comfortable with dual licensing; I can sketch a concrete 2-license text combo and a quick compliance checklist tailored to your project.