Apache License 2.0

The Apache License 2.0 grants broad permission to use, reproduce, modify, publicly display, publicly perform, sublicense, and distribute the licensed work.¹ Its permissive structure permits the work to be incorporated into proprietary software without requiring the larger product to adopt the same license. This distinguishes it from a copyleft license such as the GNU General Public License, which imposes broader conditions on certain redistributed derivatives.⁴

The license applies to copyrightable material identified as the “Work,” together with derivative works made from it. A distributor may offer the software under different terms for its own modifications, but the original licensed portions remain subject to the Apache terms. The license does not require source publication, payment of royalties, or distribution through a particular channel.

Redistribution under the Apache License 2.0 requires preservation of the license, copyright notices, and relevant attribution notices.¹ A distributor must provide a copy of the license, mark modified files with prominent notices, and retain applicable notices in a NOTICE file when the original work includes one. Those obligations concern the licensed material; they do not generally require a distributor to reproduce every notice for unrelated code.

Derivative works may carry different names, and the license does not grant permission to use the Apache Software Foundation’s trademarks or imply endorsement. The text also permits distribution of source or object form, provided the applicable conditions are met. Packaging practices therefore matter: software distributors commonly preserve license and NOTICE files in documentation, installation directories, or an accompanying legal-notices archive.

The license includes an express patent grant from contributors for patent claims necessarily infringed by their contributions or by the combination of those contributions with the work.¹ This grant is unusually prominent among permissive licenses. It terminates for a party that initiates patent litigation alleging that the work or a contribution within it infringes a patent. The provision is intended to discourage patent aggression while preserving a contributor’s ability to defend unrelated claims.

Apache License 2.0 software is supplied without warranties, and the license limits contributors’ liability to the extent permitted by applicable law.¹ It is recognized as an open-source license by the Open Source Initiative.² Compatibility is not automatic: combining Apache-licensed code with another license requires examining both licenses, and Apache License 2.0 code can be incorporated into GPLv3 projects under the Free Software Foundation’s compatibility guidance.⁴

The Apache License 2.0’s NOTICE mechanism is an attribution rule rather than a second license for the entire project.¹ A NOTICE file can contain required legal attributions and other notices, but its contents must not be used to impose terms that contradict the license. This distinction is significant for large distributions that combine many dependencies.

The license also separates copyright permission from trademark permission: copying code does not authorize use of project names, logos, or marks. In modern compliance work, the license’s standardized identifier is Apache-2.0 in the SPDX License List.³ Version 2.0 replaced the Apache Software License 1.1 and added clearer patent, attribution, and redistribution language. Companies often retain an inventory of license texts, copyright notices, and NOTICE files because failure to preserve them can jeopardize compliance even when the software itself is free to use.

Permissive license

A license that grants broad reuse and redistribution rights without generally requiring derivative works to remain under the same license.

NOTICE file

An attribution and legal-notices file that must be preserved when included with an Apache-licensed work.

Patent termination

The Apache License 2.0 provision under which the patent grant ends for a party bringing certain infringement litigation.

SPDX identifier

A standardized short identifier used to record a software license; the identifier for this license is Apache-2.0.