Licensing

picodroid-rs is dual-licensed. You can use it under either of two licenses, at your choice:

GPL-3.0-only — the default open-source license. Free to use, modify, and redistribute, subject to the terms of the GNU General Public License, version 3, with no Classpath Exception. See LICENSE for the full text.
Proprietary commercial license — available from the project maintainer for customers who need to distribute closed-source derivatives or apps. Contact rajora.shiv@gmail.com for terms.

You do not need to choose between them up front. If you only ever distribute your work as open source under GPL-3.0, you never need the commercial license. If at some point you need to ship closed-source, contact us before doing so.

Which license applies to you?

You are using picodroid as-is, for personal/hobbyist use

You can use picodroid under GPL-3.0 with no further obligation. If you do not redistribute (convey) the resulting work to anyone else, GPL-3.0 imposes no requirements on you.

You are forking or modifying picodroid itself

GPL-3.0 applies. Your fork must be released under GPL-3.0 (or a compatible license), with full source available to anyone you distribute it to. This is the standard “viral” property of GPL.

You are writing a Java app that imports the picodroid SDK (`picodroid.*`)

GPL-3.0 applies — and there is no Classpath Exception. The Classpath Exception, used by OpenJDK, allows applications to link the GPL-licensed standard library without becoming GPL themselves. picodroid does not grant that exception. This is intentional.

In practice this means: if you publish or distribute a .papk app that links any class from picodroid.app, picodroid.widget, picodroid.io, etc., your app must also be released under GPL-3.0 with full source.

If you need to ship a closed-source app that runs on picodroid, buy the commercial license — that is exactly what it is for.

You are a commercial customer building a closed-source product on picodroid

The commercial license removes the GPL-3.0 obligations. You can ship firmware images and .papk apps without releasing source, integrate picodroid into proprietary products, and modify the runtime without publishing your modifications.

Contact rajora.shiv@gmail.com to discuss terms.

Third-party components

picodroid bundles several third-party libraries (FreeRTOS-Kernel, LVGL, LZ4, littlefs-rust, cyw43-driver, the rp-hal stack, and various Rust crates). All of them are under permissive or compatible licenses (MIT, BSD-2-Clause, BSD-3-Clause, MPL-2.0, Apache-2.0, or the Raspberry Pi clause of cyw43-driver). See NOTICE for the full list and the specific terms that apply to each. The dual-license arrangement above covers only picodroid’s own code; you must still comply with the upstream terms of any third-party component you distribute.

Contributors

Contributions are accepted under an inbound license grant that lets the maintainer keep the dual-license model intact. See Contributing and CLA. The grant is non-exclusive: you keep your copyright and remain free to do whatever you want with your own contribution outside of picodroid.