# A2UI Licensing Details: Apache 2.0 Terms and Compliance Requirements

> Understand A2UI licensing under Apache 2.0. Learn compliance requirements for copyright, attribution, and redistribution of the google/A2UI repository.

- Repository: [Google/A2UI](https://github.com/google/A2UI)
- Tags: api-reference
- Published: 2026-03-13

---

**A2UI is released under the Apache License, Version 2.0, requiring you to retain copyright notices, provide attribution, and include the license text in any redistribution.**

The **google/A2UI** repository is an open-source project with specific licensing terms that govern how you can use, modify, and distribute the code. Understanding these **A2UI licensing details** is essential before integrating the library into your applications or creating derivative works.

## Apache 2.0 License Overview

A2UI is released under the **Apache License, Version 2.0**. This permissive open-source license allows commercial use, modification, distribution, and private use, provided you meet specific attribution requirements.

The top-level **[LICENSE](https://github.com/google/A2UI/blob/main/LICENSE)** file contains the complete legal text of the Apache 2.0 license. Every source file in the repository includes a standardized header comment that references this license and directs users to the official Apache license URL at `https://www.apache.org/licenses/LICENSE-2.0`.

## License Declarations in Package Configuration

As a mono-repository, A2UI declares the Apache 2.0 license in each package's configuration file. Every [`package.json`](https://github.com/google/A2UI/blob/main/package.json) within the project explicitly sets the license field to ensure clarity for NPM distribution.

For example, in **[tools/inspector/package.json](https://github.com/google/A2UI/blob/main/tools/inspector/package.json)**, the license is declared as:

```json
{
  "name": "a2ui-tools-inspector",
  "version": "0.0.1",
  "license": "Apache-2.0"
}

```

This pattern is consistent across all sub-packages, including **[tools/editor/package.json](https://github.com/google/A2UI/blob/main/tools/editor/package.json)**, **[renderers/react/package.json](https://github.com/google/A2UI/blob/main/renderers/react/package.json)**, and **[samples/client/lit/package.json](https://github.com/google/A2UI/blob/main/samples/client/lit/package.json)**. Each declaration confirms that the specific module follows the same licensing terms as the core repository.

## Source File Headers and Copyright Notices

Every TypeScript and source file in the A2UI repository contains a standardized Apache 2.0 header comment. These headers establish Google LLC as the copyright holder and reference the license terms.

A typical header reads:

> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0.

These per-file notices ensure that even when individual files are distributed separately from the repository, the licensing requirements remain clear and enforceable.

## Compliance Requirements for Redistribution

When you copy, modify, or distribute code from A2UI, you must comply with three core Apache 2.0 obligations:

1. **Retain copyright notices**: Preserve all existing copyright headers and attribution notices from the original source files.

2. **Provide attribution**: Include a NOTICE file if the original repository contains one, or maintain any attribution comments in the source code.

3. **Include license text**: Attach a copy of the Apache 2.0 license in any redistributed binaries or source distributions, typically by including the full LICENSE file.

Failure to meet these requirements violates the license terms and terminates your rights to use the software under the Apache 2.0 grant.

## Adding License Headers to New A2UI Files

When contributing to A2UI or creating derivative works, you must add the standard Apache 2.0 header to any new TypeScript files. Below is the required format:

```typescript
/**
 * Copyright 2024 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Your A2UI code here

```

If you publish a new NPM package derived from A2UI, ensure your [`package.json`](https://github.com/google/A2UI/blob/main/package.json) includes the license field:

```json
{
  "name": "my-a2ui-extension",
  "version": "1.0.0",
  "license": "Apache-2.0"
}

```

## Summary

- A2UI is licensed under the **Apache License, Version 2.0**, as stated in the top-level LICENSE file and every source file header.
- Each package within the mono-repo explicitly declares `"license": "Apache-2.0"` in its [`package.json`](https://github.com/google/A2UI/blob/main/package.json), including files like [`tools/inspector/package.json`](https://github.com/google/A2UI/blob/main/tools/inspector/package.json) and [`renderers/react/package.json`](https://github.com/google/A2UI/blob/main/renderers/react/package.json).
- You must retain copyright notices, provide attribution, and include the full license text when redistributing A2UI code.
- New files in the project must include the standardized Apache 2.0 header comment with Google LLC copyright attribution.

## Frequently Asked Questions

### What license does A2UI use?

A2UI uses the **Apache License, Version 2.0**. This is a permissive open-source license that allows commercial and private use, modification, and distribution, provided you follow the attribution and notice requirements specified in the license terms.

### Where can I find the full license text in the A2UI repository?

The complete Apache 2.0 license text is located in the **[LICENSE](https://github.com/google/A2UI/blob/main/LICENSE)** file at the root of the google/A2UI repository. Additionally, every source file contains a header comment summarizing the license and linking to the official Apache license URL.

### Do I need to include the license header when using A2UI code in my project?

Yes, you must retain the existing copyright headers and license notices from any A2UI source files you use. When creating new derivative works or copying code, preserve the original Apache 2.0 headers, or ensure your project includes the full LICENSE file and proper attribution to Google LLC as required by the Apache 2.0 terms.

### Can I use A2UI in commercial applications?

Yes, the Apache 2.0 license explicitly permits commercial use. You can integrate A2UI into proprietary products, modify the code, and distribute binaries, provided you comply with the license requirements: retaining copyright notices, providing attribution, and including the Apache 2.0 license text with your distribution.