Measuring emissions is only the beginning
When ISO/IEC 21031:2024 was published, organisations gained a rigorous methodology for calculating software carbon intensity, but internal measurement work isn’t visible outside the organisation. With regulations like the Corporate Sustainability Reporting Directive (CSRD) extending their scope to include software emissions, and procurement requirements emerging, the expectation for consistent and verifiable disclosures is growing. Calculating your SCI score is the foundation; publicly disclosing it is what turns that work into accountability.
Benefits at every level
Every disclosure contributes to the shared body of reference data the industry needs to make meaningful progress on software sustainability.
For your organisation
Brings internal measurement work into a publicly recognised disclosure — giving procurement teams, auditors, and regulators a consistent reference point as transparency requirements grow.
For your stakeholders
Provides a transparent, structured record of your software’s carbon intensity that clients, partners, and supply chain reviewers can incorporate into their own reporting with confidence.
For the industry
Each approved disclosure joins a publicly accessible body of methodology and results that researchers, benchmarkers, and policymakers can build on — turning individual measurement work into collective infrastructure.
The disclosure, not the score
GSF certifies that an organisation has completed and publicly disclosed an SCI calculation with sufficient detail for the community to understand and evaluate it. We verify that all required information is present, not that the methodology is sound, the arithmetic is correct, or the score is accurate. Responsibility for accuracy and conformity with ISO/IEC 21031:2024 sits entirely with the applicant through self-attestation. This keeps the programme lightweight and accessible while public disclosure provides the credibility: anyone can read your submission and assess it for themselves.
A 7-section questionnaire
About you and your software — organisation, contact, software name, version, and a brief description
SCI score — your score with units (e.g. gCO2eq per 1,000 API requests) and the measurement period
Software boundary — included components, excluded components with rationale, and how shared infrastructure is handled
Functional unit (R) — the unit you chose, why it reflects how your software scales or delivers value, and how you counted it
Energy and carbon intensity (E, I) — total energy with PUE, per-component breakdown with data sources, and carbon intensity with location, approach, and source
Embodied emissions (M) — total M with unit (or a specific justification if M=0), plus per-component breakdown with sources if M>0
Methodology and calculation — approach (measurement, calculation, or hybrid), at least one specific assumption and limitation, and the full SCI calculation shown with your actual numbers
Attestation — the 10-point attestation from the template, signed and dated
How certification works
From submission to certificate in typically 3–4 weeks. The process is lightweight by design — if your SCI calculation is done, most of the work is already done.
1. Self-attestation questionnaire
The applicant completes a 7-section questionnaire covering their SCI methodology, boundary, functional unit, energy and carbon data, embodied emissions, and full calculation. A signed attestation is included. Liability for accuracy sits with the applicant.
2. Completeness review
A reviewer assesses the submission against a 7-item checklist, asking whether each section is detailed enough for a practitioner to understand and evaluate the calculation. Review takes 10–15 business days. Incomplete submissions receive specific revision feedback — this is not a rejection.
3. Software Standards Working Group sign-off
The Software Standards Working Group has a 7-day objection period. Any member may raise a specific objection; in practice, most submissions proceed without one. This is a governance safeguard, not a full technical review.
4. Sign-off
The GSF Executive Director or Chair reviews the outcome of the working group sign-off period and issues the certificate.
5. Publication
The certificate is issued and the full submission is published publicly on GitHub. Your contact email is redacted; everything else is published as submitted. Public disclosure is what gives self-certification its credibility — anyone can read and assess your methodology.
6. Annual renewal
Certificates are valid for one year. Organisations must resubmit annually to maintain their certification status.
Get Involved
Whether you’re ready to apply, want to deepen your understanding of the SCI, or have a question, here’s where to start.
