License

Unless stated otherwise, ASF is licensed under Apache License 2.0. For a quick overview what you can and cannot do, you can use tl;dr Legal.

ASF license is very permissive and you're allowed to do much more than in standard GPL license, including using ASF in commercial projects without a requirement of making code open-source. In short, as stated by tl;dr Legal:

You can do what you like with the software, as long as you include the required notices. This permissive license contains a patent license from the contributors of the code.

By stating that ASF is licensed under Apache License 2.0, we refer to the main project only, including its source code, without making any statements about other projects that ASF makes use of (especially libraries, tools, frameworks and frontends, such as ASF-ui), which are typically licensed under different terms.

Remarks

If you're creating your own software/service based on ASF or part of its code, please review point 6 of the license:

Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.

We do not grant you direct permission to use ASF/ArchiSteamFarm product name in your own software, but we allow using it in some common-sense scenarios:

You can:

Claim that your software/service is based on ASF (or its code)
Refer to your software/service as ASF fork
Claim that your software/service is powered by ASF, if you didn't do any changes to the source code
Use ASF for various reference purposes, such as linking software/service origin, our wiki, or "as required for reasonable and customary use in describing the origin of the Work"

You cannot:

Claim that your software/service is ASF
Refer to your software/service as ASF
Claim that your software/service is powered by ASF, if you did any changes to the source code
Use false advertising, such as stating that ASF or its developers are affiliated with your software/service

If in doubt, please contact with us, and we'll be happy to answer your legal/licensing questions.