Evidence before assertion
Claims should be supported by evidence wherever possible. Where evidence is unavailable, the limitation should be recorded.
Purpose, principles and perspective
About SDAF
SDAF was created to make environmental impact a visible, evidence-backed and accountable part of digital architecture decisions.
Rather than adding sustainability after a decision has been made, the framework brings environmental, financial and lifecycle considerations into the decision itself.
Why SDAF exists
Many organisations measure sustainability outcomes after implementation, when architecture, procurement and lifecycle choices have already shaped much of the impact.
Through architectural and sustainability work, a recurring gap became apparent: decisions were made with incomplete evidence, environmental considerations arrived too late, assumptions disappeared between analysis and reporting, and sustainability metrics remained separate from business decisions.
SDAF was developed to address that gap. It gives technical, environmental and business perspectives a shared decision process, with explicit boundaries, comparable options and reasoning that can be reviewed.
The purpose is to improve the quality, transparency and reviewability of sustainable digital decisions while complementing existing standards, regulations and specialist methodologies.
Principles behind SDAF
Several principles have influenced the framework from the beginning.
Visible assumptions
Assumptions should remain explicit and reviewable throughout analysis, recommendation and reporting.
Lifecycle thinking
Architecture decisions should consider manufacturing, operation, retention and end-of-life, with the assessment boundary made clear.
Confidence matters
Evidence quality influences how strongly a conclusion can be relied upon. Confidence and calculated impact should remain separate.
Reviewability
A reviewer should be able to understand the decision, its trade-offs and its conditions long after the original analysis.
Sustainability as an engineering discipline
Sustainability belongs in planning, design, procurement and operation, alongside the other requirements architecture must address.
Open by design
SDAF is intentionally public. Transparency, traceability and reviewability are central to its approach, and the framework should be open to the same scrutiny it asks of a decision.
The methodology is openly published, the assessment approach is documented, and assumptions and decision reasoning are intended to remain visible. Independent use, review and challenge help expose weaknesses and improve the method.
The goal is to make the reasoning behind an answer visible, so others can understand it, question it and apply it in their own context.
Read the methodology and change history on GitHub. Framework content is licensed under CC BY 4.0, except where otherwise noted; software and third-party materials may have separate terms.
Raymond du Toit · Creator and steward
About the founder
Raymond du Toit brings more than 26 years of experience in IT architecture and consulting, with a background spanning enterprise architecture, resiliency, cloud and infrastructure.
“During years of architecture and sustainability work, I repeatedly saw environmental impacts discussed after a decision had already been made. SDAF emerged from a simple question: how can we understand the consequences of a choice before committing to it?”
Raymond du Toit
A later focus on sustainability and lifecycle thinking connected those technical, environmental and business perspectives. The motivation was to turn sustainability from aspiration into practical decision support.
The founder's role is to develop and steward the framework while leaving space for others to challenge it, use it independently and contribute to its evolution.
Who SDAF is for
SDAF is intended for architects, sustainability practitioners, procurement teams, decision owners and organisations seeking a more transparent and evidence-based approach to sustainable digital decisions.
What success looks like
Success means helping people make better decisions. Useful outcomes include:
- Understanding trade-offs more clearly.
- Making assumptions visible and reviewable.
- Improving the quality of evidence.
- Strengthening decision governance.
- Supporting more informed sustainability outcomes.
The number of calculations or reports is secondary to the quality of the decision they support. Long term, the aspiration is for evidence-based sustainability decision-making to become a normal part of digital architecture practice.
What SDAF is not
SDAF is a decision-support methodology, not a decision-making authority.
- It is not a sustainability reporting platform.
- It is not a certification scheme.
- It is not a compliance standard.
- It is not a standalone carbon calculator.
- It does not replace professional judgement.
Calculations can inform an assessment, but the decision still requires appropriate evidence, declared boundaries, qualified review and accountable ownership. Using SDAF does not establish compliance, certification or a guaranteed outcome.
Looking forward
SDAF is still evolving. The framework, Studio and supporting materials are intended to improve through practical use, critique, discussion and experience.
Feedback, challenge and independent application are welcomed. The aim is to contribute to a more transparent and evidence-based approach to sustainable digital decision-making that people can use without becoming dependent on a tool or an individual.