What License Does Needle Use? Apache 2.0 Explained

Needle is released under the Apache License, Version 2.0, a permissive open-source license that allows commercial and private use, modification, distribution, and sublicensing with minimal requirements.

If you're considering adopting Needle for your machine learning or tensor computation workloads, understanding its licensing terms is essential for compliance. The Apache 2.0 license offers significant flexibility compared to copyleft alternatives, making Needle suitable for integration into both open-source and proprietary projects.

Apache 2.0 License Terms for Needle

The Needle repository at cactus-compute/needle explicitly adopts the Apache 2.0 license. This license framework provides four core guarantees to users:

• Unrestricted usage rights — Use Needle in personal, academic, or commercial projects without licensing fees
• Modification freedom — Create derivative works and distribute modified versions
• Patent protection — Receive explicit patent grants from contributors, reducing litigation risk
• Permissive redistribution — Incorporate Needle into larger projects under different license terms

According to the Needle source code, the full license text resides in the repository's LICENSE file at the repository root. The pyproject.toml build configuration also references this license in its project metadata.

License Compliance Requirements

While Apache 2.0 is highly permissive, it imposes specific obligations you must satisfy when using or redistributing Needle:

1. Preserve copyright notices — Include the original license text and attribution in any distributed copies
2. State changes — Document any modifications you make to the source code
3. Include license copy — Distribute the Apache 2.0 license text alongside the software

These requirements are minimal compared to GPL-style licenses, which would force derivative works to adopt the same license terms.

Verifying Needle's License Programmatically

You can confirm Needle's license directly from Python code using standard library tools. This approach pulls metadata from the installed package:

import importlib.metadata as metadata

def get_needle_license():
    dist = metadata.distribution('needle')
    return dist.metadata['License']

print("Needle license:", get_needle_license())

# Expected output: Apache-2.0

This verification method references the package metadata defined in pyproject.toml, ensuring you're checking the authoritative source rather than documentation that might lag behind actual releases.

Adding Apache 2.0 Headers to Needle-Based Projects

When creating new files that incorporate or extend Needle functionality, follow this standard header format:

# Copyright (c) 2024 <Your Name>

#

# 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

#

#     http://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.

Including this header in your project's source files clarifies licensing boundaries and satisfies Apache 2.0 documentation requirements.

Key License Files in the Needle Repository

File	Location	Purpose
LICENSE	Repository root	Complete Apache 2.0 license text
pyproject.toml	Repository root	Build configuration with license metadata
README.md	Repository root	Project overview and basic usage
needle/__init__.py	Package directory	Public API entry point

The pyproject.toml file explicitly declares the license as Apache-2.0 in its project table, which packaging tools use when publishing to repositories like PyPI.

Configuring Your Project to Match Needle's License

If you're building an application that depends on Needle, explicitly declare your compatible license in pyproject.toml:

[project]
name = "my-needle-app"
license = {text = "Apache-2.0"}   # Mirrors Needle's license

Matching Needle's license eliminates compatibility concerns and simplifies legal review processes in enterprise environments.

Summary

• Needle uses Apache License 2.0, confirmed in the LICENSE file and pyproject.toml metadata
• Apache 2.0 permits commercial use, modification, and proprietary integration with attribution requirements
• Compliance requires preserving notices and documenting changes, but imposes no copyleft obligations
• License verification is available through Python's importlib.metadata module
• File headers and pyproject.toml declarations ensure proper attribution in derivative projects

Frequently Asked Questions

Is Needle free for commercial use?

Yes. The Apache 2.0 license explicitly permits commercial use without licensing fees or revenue sharing requirements. You can incorporate Needle into products you sell, provided you include the license text and any required attributions.

Do I need to open-source my code if I use Needle?

No. Apache 2.0 is not a copyleft license. You can use Needle in proprietary, closed-source applications without releasing your own source code. This contrasts sharply with GPL-licensed alternatives that would force derivative works to adopt the same license terms.

Where can I find the exact license text for Needle?

The complete license text is available in the LICENSE file at the repository root (github.com/cactus-compute/needle/blob/main/LICENSE). This file contains the unmodified Apache 2.0 text as published by the Apache Software Foundation.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}