Understanding the LGPL-3.0 License
The helpers4 Rust crate is licensed under the GNU Lesser General Public License v3.0 or later (LGPL-3.0-or-later), like every helpers4 project. Here’s a practical summary, including what is specific to Rust.
What is LGPL-3.0?
Section titled “What is LGPL-3.0?”LGPL-3.0 is a weak copyleft license, mainly designed for libraries. It allows broad use (including commercial use), while requiring that changes to the LGPL-covered code remain under the LGPL when distributed.
What you can do
Section titled “What you can do”As an individual
Section titled “As an individual”- ✅ Use helpers4 freely in personal projects
- ✅ Study, modify, and redistribute the source code
- ✅ Use it in your portfolio, side projects, or learning exercises
- ✅ Contribute back to the project
As a non-profit / NGO
Section titled “As a non-profit / NGO”- ✅ Use helpers4 in internal tools and public-facing applications
- ✅ Modify the code to fit your needs
- ✅ Distribute software that uses helpers4
As a company
Section titled “As a company”- ✅ Use helpers4 in proprietary or open-source products
- ✅ Use helpers4 in internal tools
- ✅ Run SaaS / network services using helpers4
What you must do
Section titled “What you must do”| Requirement | Details |
|---|---|
| Keep notices | Keep copyright and license notices for LGPL-covered code |
| Provide LGPL text | Include a copy of the LGPL license when distributing |
| Publish LGPL modifications | If you distribute modified LGPL-covered code, provide corresponding source under LGPL |
| Allow relinking | When you distribute a program that includes helpers4, do not block the recipients from replacing helpers4 with a modified version (see below) |
What you cannot do
Section titled “What you cannot do”- ❌ Remove or alter copyright/license notices on LGPL-covered code
- ❌ Re-license LGPL-covered code as proprietary
- ❌ Distribute modified LGPL-covered code without preserving LGPL obligations
What is specific to Rust
Section titled “What is specific to Rust”Cargo compiles a dependency into your final binary (static linking). The LGPL-3.0 (section 4, “Combined Works”) asks that whoever receives such a binary can replace helpers4 with a modified version and rebuild the combined work. In practice:
| Your situation | What it means |
|---|---|
| You publish your application’s source (open source, or shared with your customers) | Nothing more is needed: anyone can rebuild it against another version of helpers4 |
| You distribute a closed-source binary | Provide what is needed to relink it (for example the object files and build instructions) or otherwise make helpers4 replaceable, and keep the helpers4 license notice with the product |
| Your software is only used internally, or runs as a hosted service | The conditions are triggered by distributing the binary, not by running it |
In short
Section titled “In short”You can use helpers4 in commercial, closed-source, and SaaS contexts. LGPL obligations apply only to the LGPL-covered code and its distributed modifications; for a Rust binary you distribute, they include letting recipients relink it.
Full license text
Section titled “Full license text”The complete license text is available at gnu.org/licenses/lgpl-3.0 and in the LICENSE file of the repository.