Open Source Initiative

The Open Source Definition spells out the essential qualities of Open Source software. Compliance with the definition allows software developers to call their software Open Source, and to use our service mark.

Since the community needs a reliable way of knowing whether a piece of software really is open source, OSI is registering a trademark, Open Source Initiative Approved, for this purpose. If you see this mark on a piece of software, either the software really is being distributed under a license that conforms to the Open Source Definition, or the distributor is misusing the mark and thereby breaking the law.

The Open Source Initiative Approved mark applies to software, not to licenses. What people really want to know is that a package consisting of software together with its accompanying license is an open source distribution. Also, licenses alone probably wouldn't qualify as "goods", which is what the U.S. Patent and Trademark Office registers certification marks for. However, software authors obviously have to be able to identify their distributions as Open Source Initiative Approved software, when appropriate, without asking us. Authorization to use the service mark comes in two steps:

• OSI maintains a list of Open Source licenses licenses that conform to the Open Source Definition, have been through public scrutiny, and have been approved by us. If you have a license that you would like added to this list, please follow the approval process.
• If you want to use the Open Source Initiative Approved mark on your software, you can do this by distributing the software with an approved license from the list and marking the software appropriately.

Using the Mark

You may use the Open Source Initiative Approved mark on any software that is distributed under an OSI-approved license.

To identify your software distribution as Open Source Initiative Approved, you must attach one of the following two notices, unmodified, to the software, as described below. The full notice is:</>

This software is Open Source Initiative approved Open Source Software.
Open Source Initiative Approved is a trademark of the Open Source Initiative.

The shorter notice is:

Open Source Initiative Approved Open Source Software

Each form of distribution of your software has its own requirements:

• If the software is being distributed in electronic form (not in tangible form), you must put the full notice in a README file, or other similar file intended to be the first file that a human user would read.
• If the software is being distributed in tangible form, you must do all of the following that are applicable:
• • If the software is distributed with any accompanying printed matter, you must place the full notice in the printed matter.
  • If the software is distributed on removable information media such as diskettes, CD-ROM, cartridge tape, etc., on which it is physically possible to place at least the shorter notice in a manner that can be read by the unaided human eye without impairing the functioning of the media, you must place either the full or the shorter notice on the media.
  • If the tangible object containing the software is distributed in a package that prevents the notice (if any) on the object from being read, you must place the full notice on the outside of the package.

If none of the above apply to your distribution, contact us, and we'll add guidelines for your situation to this list.

You can also browse a list of OSI-approved licenses.