Open Source

Open-Source Under Apache 2.0 – An Accessible, Transparent Approach

The Halo initiative is developed under the permissive Apache 2.0 license, which enables any organization—be it a measurement company, Joint Industry Committee (JIC), or another stakeholder—to freely adopt, adapt, and build upon the Halo code proposals.

This open-source philosophy does not enforce a single usage model or standardized metric; rather, it provides a voluntary foundation that promotes transparency, fosters accountability, and supports continuous innovation in cross-media measurement.

The Apache 2.0 license and open-source framework underpin a voluntary, dynamic environment where local measurement bodies and JICs can adapt Halo to meet advertiser demands and local realities. Through this approach, the Halo Initiative unites transparency with innovation, driving the entire industry forward on its own terms, free from restrictive IP or mandated metrics.

Why Apache 2.0?

No Licensing Barriers

Under Apache 2.0, all parties have the right to use, modify, or redistribute the Halo code without incurring fees or entangling themselves in restrictive intellectual property agreements. This lowers the cost of experimentation and encourages diverse local innovations.

A Truly Open & Inclusive Community

Apache 2.0 allows measurement organizations, advertisers, media owners and even individual developers to review, audit and enhance the Halo Framework as they see fit. The absence of complex IP constraints means any contributor can suggest improvements or tailor the code for their regional or methodological needs.

Clear, Transparent Governance

The license includes robust guidelines to protect contributors and users alike, ensuring that any derivatives or enhancements remain clearly documented. This clarity helps the entire Halo Community maintain consistent, open collaboration without hidden obligations.

Core Principles of Our Open-Source Approach

Maximum Transparency

Every line of the Halo Framework’s code is publicly visible, encouraging peer review by measurement experts, JICs, agencies, advertiser associations, party audit bodies or any other organisation with an interest in media measurement. This openness reassures stakeholders that no single player can insert partial or self-serving elements into the framework.

Shared Accountability & Neutrality

Halo’s development follows an open, peer-reviewed merge process. Proposed changes or new features require community feedback and must align with Halo’s founding principles (neutrality, privacy, advertiser “North Star” alignment). This ensures the codebase remains fair for all media channels, big or small.

Permission & Protection

Apache 2.0 offers a broad license granting permission to use the Halo code for any purpose, while also protecting contributors through disclaimers and indemnities. This balanced approach encourages collaboration, fosters a healthy ecosystem, and removes fear of IP infringement.

Sustainable Innovation

By lowering barriers to entry and spurring diverse local adaptations, open-source collaboration fuels continuous improvement. Whether your organization is a large measurement provider integrating advanced cryptography or a smaller JIC refining local metrics, you can tap into a collective knowledge base that grows with each contribution.

Contributing to the Halo Initiative

Explore the Repository

Browse open issues, review existing merges or read architectural summaries. You’ll find comprehensive documentation, from cryptographic modules to guidelines on bridging panel data with digital logs.

Submit Pull Requests

Propose enhancements or bug fixes, engage in peer-review discussions and see your contributions shape the Halo Framework. All merges must align with Halo’s neutrality, privacy, and user-centric priorities.

Concept Review

Significant new features or methodology expansions may need conceptual review to ensure they respect the advertiser-driven North Star. WFA staff help coordinate these larger efforts, keeping them transparent and compliant with Halo’s open-source ethos.