I'm not sure if the distinction between free and open source software makes a difference for this question, so I'll use the term FOSS.

Can a FOSS platform make API calls to proprietary systems, such as Wolfram Alpha?

  • A typical example was some old GNU emacs or GCC compiled from source code to run on a then proprietary SunOS4. I did that about 30 years ago and stated that publicly. Nobody sued me (or my employer). But details depend upon your legal system. I am French, but I am not a lawyer (and not your lawyer) May 28, 2020 at 17:02
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    Every Facebook user with an Android phone uses the Linux network stack to make API calls to Facebook. May 28, 2020 at 19:28

1 Answer 1


Yes, that is possible.

Even for a strong copyleft license like the GPL, when two applications communicate "at arms length" with each other, then the two applications are considered to be independent works and their copyright licenses don't affect each other.

The determination if two pieces of code communicate "at arms length" revolves mostly around if they execute in the same process context, if they use a communication mechanism typically used for inter-process communication and if you need to have knowledge of the implementation to reproduce the datastructures used in the communication.

For using a published web-API, all of these indicators point to independent works.

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