LICENSE.md

LICENSE.md is the conventional file placed at the root of a code repository to declare the legal license under which the project is distributed. It answers a simple, load-bearing question for anyone who finds the code: what am I allowed to do with this? By naming a recognized license — MIT, Apache 2.0, GPL, and so on — the file sets the permissions, conditions, and limitations that govern use, modification, and redistribution.

• A recognized license identifier - Usually a standard SPDX license so tools and humans both know the terms.
• A root, well-known filename - LICENSE, LICENSE.md, or LICENSE.txt, where GitHub and package managers auto-detect it.
• Permissions, conditions, and limitations - Spells out attribution, copyleft, patent grants, and warranty disclaimers.
• Machine-readable licensing - Lets scanners and dependency tools flag license compatibility across a stack.

For APIs, the LICENSE file is where the licensing question splits in two: the license on the code (SDKs, server implementations, specs) versus the terms on the API service and its data, which usually live in separate terms of service. A missing or ambiguous LICENSE is one of the fastest trust and compliance gaps to spot in an API’s repositories, and its presence is a cheap, machine-checkable signal that a provider has thought about how others may reuse their work — the same reason I care about a clean README.md or a published security.txt.