zeromq

What license is ØMQ released under?

ØMQ is released under the GNU General Public License V3. Essentially, this means that you get the full source code of ØMQ, and you can distribute and modify it, provided that you ship all modifications under the GPL as well.

Can I buy a commercial license for ØMQ?

If you are an individual end user, there is generally no need to purchase a commercial license, provided that you respect the terms and conditions of the GPL.

As an enterprise customer, we encourage you to purchase a commercial license from FastMQ Inc. and receive benefits such as support for mission-critical use of ØMQ. We also encourage ISVs and IHVs to incorporate ØMQ into their offerings, either based on the GPL or preferably through a custom license deal with FastMQ Inc. Please contact FastMQ Inc. for additional information.

How can ØMQ be both open source and commercially licensed?

This is called "dual licensing". Since FastMQ Inc. held all the copyrights to the ØMQ code, or is at least permitted to relicense code that is owned by external contributors or other parties, we are free to choose the terms under which we license the code to our customers, or the open source community.

Why dual licensing?

We — like other companies — believe that dual licensing gives both developers and users the best of two worlds. While anyone is free to look at the code and even improve it, commercial licenses support the company and allow for professional maintenance and support. The open source community gets more high-quality free software at no cost, while businesses can rely on quality support from our first-hand developers. Both worlds profit from each other: The commercial licenses support both our business and the open source community, and vice versa.

Will the licensing terms of ØMQ be changed in the future?

We are not currently planning to do so, but it doesn't really matter. Any code that was once released under the GPL cannot be "closed" again. The license that FastMQ Inc. has granted you with the GPL is perpetual and cannot be taken back. Even if FastMQ Inc. wanted to change the license again, this could only affect future versions, and anybody would still be permitted to redistribute the existing ØMQ code under the terms of the GPL.

Which guidelines apply to the use of the name ØMQ?

The term ØMQ has been registered by FastMQ Inc. as a trademark. It may be freely used together with the products available from this web site. However, if you choose to ship custom binaries and/or source code revisions of the product, FastMQ Inc. reserves the right to deny use of the trademark ØMQ. This might seem rather strict but we believe that it is important to avoid any kind of confusion arising from multiple versions of the same product coming from different sources.

What about software patents?

FastMQ Inc. offers ØMQ free of charge to anyone who finds it useful. The only restrictions we impose are those of either the GPL or our respective commercial licenses — whichever you choose. This also means that we will not restrict your use of the product by means of patents. However, should someone attempt to abuse the product, e.g. by violating the GPL or our commercial license, we will make use of our intellectual property rights to protect ØMQ.