The Footprint Manager Demo: VSME-Aligned Carbon Accounting for SMEs

An SME that wants to measure its own carbon footprint has a hard choice. Spreadsheet in Excel — and spend a week reconciling factor versions. Buy an enterprise ESG platform — and spend €15–50k per year for tooling designed for 500-seat companies. Or outsource to a sustainability consultancy — and get a beautiful PDF that you cannot reproduce, audit, or adjust without paying again.

We built the Footprint Manager because none of those options fit us. This post is a tour of what it does, with a live demo populated by Regen Studio's real 2025 inventory. The companion post walks through the numbers themselves; this one is about the tool.

What it is

The Footprint Manager is a local-first, VSME-aligned carbon accounting tool for SMEs. It runs on a laptop (Python + SQLite, zero external dependencies), produces machine-readable inline-XBRL reports per the EFRAG VSME taxonomy, and keeps a full audit trail of which emission factors were used at the moment of calculation.

It is explicitly not trying to be an enterprise platform. There is no SSO, no multi-tenant SaaS back-end, no "AI-powered sustainability insights", no carbon-credit marketplace bolted on. It measures. That is the feature.

The eight views

The demo walks through eight pages in sequence — each one corresponds to a question an SME reporter needs to answer.

1 · Home — the live dashboard

Total emissions with an uncertainty range (not a point estimate), a scope-family donut, a management summary field, and a "primary reduction lever" that surfaces the single biggest contributor. For Regen Studio in 2025 it shouts BUSINESS TRAVEL, 7.74 t, 89.9% of total. No ambiguity.

2 · Register — the 34-row activity ledger

Every emission source, every quantity, every factor, every range. One row per activity. No hidden cells, no linked spreadsheets. The register is filterable by scope, sub-category, and date. In the demo, form submission is deactivated — the existing rows are browsable but you cannot add new ones.

3 · Disclosures — the VSME panel

Six Basic-module disclosure tables plus one Comprehensive-module table, covering: basis of preparation, methodologies and GWP source, energy consumption and mix, renewable share, water (flagged not material for our case), biodiversity, pollution, waste, workforce composition, governance, and transition plans. If a topic is not material, the tool prompts for a written basis — blank "not material" fields are not acceptable under VSME.

4 · Factors — the sourced-and-dated catalogue

Every emission factor we use, with its source, publication year, uncertainty type (range, lognormal, etc.), quality rating, and geographic scope. Factors are versioned: INSERT-only, never UPDATE. A factor from DEFRA 2024 stays labelled DEFRA 2024 forever; if DEFRA 2026 changes the number, it enters as a new row, and past reports that cited DEFRA 2024 remain reproducible.

5 · Report — the blog-ready output

The full inventory rendered as a single-scroll VSME-aligned report. Management summary, method, totals by scope, sub-category breakdown, full register, intensity ratios, energy mix, disclosure tables, reduction pathway chart against the SBTi 1.5°C trajectory, and (if enabled) inline-XBRL tagged disclosures. This is the document you send to a counterparty or publish on your own site. A --finalize flag locks the period so later edits require a versioned re-open.

6 · Methodology — the living reference

Every methodological choice documented in prose: how we picked factors, why we include RFI on flights, what "material" means in VSME, how uncertainty ranges are propagated, what we exclude. This is what an auditor reads before opening the register.

7 · Guide — the onboarding walk-through

A six-step flow for a first-time user: set your organisational boundary, pick a reporting period, enter your activities, check the factor coverage, run the estimate, review the disclosure tables. The demo has this populated so you can see what "done" looks like.

8 · Glossary — the terminology decoder

Eighteen terms, from GHG Protocol scope codes to VSME module names to IPCC GWP values. Carbon accounting has a lot of jargon; the glossary is where you decode it without leaving the tool.

Things worth noticing

Ranges, not points

Every row carries a 5th–95th percentile range. The total rolls up via log-space uncertainty propagation, so the output range is asymmetric around the central estimate. You will see 8.61 t (7.73 – 9.72), not "8.61 tonnes". The tool also refuses to accept a row where the upper/lower ratio exceeds 100× — if it trips, a factor is 200× wrong and needs investigating.

Dual Scope 2

Location-based and market-based electricity are reported as two separate rows, both visible in the register. The total uses the market-based figure per GHG Protocol convention; the location-based value sits alongside for transparency. For countries without a formal residual-mix system (Brazil), market-based equals location-based by guidance.

Factor hash as audit receipt

Every calculation run writes a calculation_runs row with a SHA-256 hash of the entire factor set used. The hash is the audit trail. Re-running with the same hash gives the same answer; a different hash signals a factor version change and makes the divergence investigable.

Inline XBRL for VSME

The HTML report is also a valid iXBRL document, with every disclosure point tagged against the EFRAG VSME taxonomy. A regulator, counterparty, or procurement tool can machine-read the numbers without scraping. The tool ships a compact catalogue of concepts and prefers official EFRAG XSDs when present.

Privacy and infrastructure

The Footprint Manager runs locally. SQLite file on your machine. No cloud tenant, no vendor, no data leaving your device unless you explicitly export a report. For an SME handling sensitive supplier data, this is the difference between "can we even use this" and "where do we sign".

Who this is for

SMEs responding to counterparty ESG questionnaires. If Philips, Unilever, or a government procurement office asks for your Scope 1/2/3 numbers, you need an answer that holds up. The Footprint Manager produces a VSME-aligned report that is the right shape for that conversation, without pretending you are the size of Philips.

Sustainability-curious founders and operators. You want a number, you do not trust consultancy invoices, you are comfortable running a Python script, and you want to understand why each row is what it is. The tool is designed to be legible — open the code, trace the calculation, audit the factor.

DPP and ESPR implementers. Product-level carbon data is about to become a regulated field on every product sold in Europe. Understanding corporate-level accounting — and the factor provenance infrastructure it requires — is foundational to doing product-level accounting credibly.

ESG advisors and accountants for SME clients. If you service 10–50 SME clients and need a reproducible workflow that you can hand over to the client at the end, this is a tool that fits that model. Everything is versioned, hashed, and file-based.

What it is not (yet)

The roadmap is public and the tool is an early product. It does not yet have: multi-user collaboration, audit-firm sign-off workflow, PDF export polish beyond the single-scroll HTML, carbon-credit retirement tracking, a Monte Carlo simulator for stress-testing the uncertainty model, or integration with accounting packages for auto-pulling activity data. Some of these are Phase 2 work; others (cross-validators with EcoLogits, auto-generated carbon.txt manifests) are Phase 3.

It is also not a replacement for professional review if you are a large company. What it does well is: produce a defensible, auditable, machine-readable baseline for an SME operating in voluntary-disclosure territory.

Deploying it for your business

The demo is read-only by design — we want you to browse freely without worrying about breaking anything. If you want the tool to work with your data (your factor set, your organisational boundary, your reporting year), reach out. We deploy it either as a self-hosted local install that you own outright, or as a managed service where we handle the accounting operations and you review the output. Either way, the code and the data remain yours.

Curious how this fits into the broader regulatory picture? The third post in this series explains the EFRAG Voluntary SME Standard — what Basic and Comprehensive modules cover, how materiality works under VSME, and why this is the right disclosure shape for SMEs even when CSRD does not apply.

Interested in deploying the Footprint Manager for your organisation? info@regenstudio.world.