Harnest or Greenly: carbon, double materiality, and CSRD comparison

The 2 tools in one sentence

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Greenly measures greenhouse gas emissions and generates a reusable dataset for around fifteen regulatory frameworks.

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Harnest manages all of a company's non-financial data, including its emissions, and preserves the reasoning behind every conclusion.

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Both calculate your carbon footprint across all three scopes. Both cover CSRD

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How to make your decision

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Ask yourself one question: what will you do next year?

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If you are simply producing and publishing a carbon footprint, measurement is enough. Choose the tool that best suits your needs (interfaces & collaboration).

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If an auditor asks why you chose one issue over another, who validated a specific value, or what assumptions a figure is based on, then the data model matters more than the calculation engine. This is where the two platforms diverge.

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Greenly, starting with measurement

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Greenly starts with spending and activity. The platform cross-references your accounting and physical data with 350,000 emission factors and automatically matches your expenses.

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It covers scopes 1, 2, and 3 using both physical and monetary approaches, offers a life cycle assessment module based on ISO 14040, 14044, and 14067 standards, and exports in xHTML format with XBRL tagging and European taxonomy.

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It collects over 320 ESRS data points, analyzes your suppliers' public data, extracts PDFs, and sends automated follow-ups. Its audit logs are timestamped and accessible to ISSA 5000 certified auditors.

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In its own domain, Greenly is comprehensive.

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Harnest, starting with the challenge

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Harnest breaks down your business into lines of activity, each with its own sector, country, subsidiary, and revenue. Each line of activity carries a value chain divided into links.

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On this framework, the platform identifies your impacts, risks, and opportunities. A negative impact carries a scale, scope, and irremediability, and links to the actions addressing it.

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Regarding carbon, Harnest calculates scopes 1, 2, and 3 according to the GHG Protocol using 270,000 ADEME, DEFRA, and EPA factors, covers the French regulatory BEGES, and calculates a simplified life cycle assessment by product reference.

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Regarding data collection, over 4,000 standardized data points cover thirteen actionable frameworks, including ESRS.

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What you will do differently on a daily basis

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Identify your key issues

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• Greenly applies an internal double materiality methodology, with automated sector-based scoring aligned with EFRAG. You receive a score.

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• Harnest lays out the calculation: you choose the criteria aggregation method, the weight of each, the points per value, and the materiality threshold. The final designation of an issue remains a human decision. When an auditor asks why this issue and not another, the configuration provides the answer.

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Map your value chain

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• Greenly analyzes your suppliers' public data, extracts PDFs, and sends automated follow-ups.

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• Harnest breaks down each line of business into links, including its sector, country, stakeholders, and a confidence level for each link. You know which data comes from suppliers and which comes from sector averages.

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Consult your stakeholders

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• Greenly manages supplier engagement and progress tracking.

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• Harnest structures a stakeholder repository into four categories with fourteen qualification attributes. Engagement campaigns are categorized, and every insight is tracked by participant. ESRS standards require proof of this consultation: this audit trail serves as that evidence.

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Collect and validate your data

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• Greenly collects over 320 ESRS data points, automatically calculates quantitative metrics, and offers API connectors.

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• Harnest covers over 4,000 standardized data points across thirteen actionable frameworks, including ESRS. The API allows you to feed and export data from your other systems, and sub-indicators by activity, subsidiary, or site are consolidated at the corporate level. Each data point is assigned an Owner, a Validator, and an external auditor, locks after submission, and retains its methodology, assumptions, and confidence level. You can carry over context from the previous year.

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Connect your strategy to your operations

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• Greenly does not document a strategic layer.

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• Harnest structures three levels: three- or five-year strategic plans, strategic pillars linked to Sustainable Development Goals, and initiatives. Each level connects to actions, targets, data points, and sustainability issues. Your executive committee sees the ambition, your teams see the tasks, and the link between the two is built into the platform.

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Manage your actions and targets

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• Greenly offers action plans, an action library, and SBTi trajectory tracking.

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• Harnest also tracks an SBTi trajectory within its carbon module. Actions are linked to the impacts they address, quantified in annualized OPEX and CAPEX with a link to your financial statements, and tracked via Gantt or Kanban task views. Each target includes its methodologies, assumptions, data sources, underlying scientific evidence, and the stakeholders involved in its definition.

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Producing and validating the report

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• Greenly exports in xHTML with XBRL tagging and integrates the European taxonomy. Its audit logs are timestamped and accessible to ISSA 5000 certified auditors.

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• Harnest builds the report collaboratively. You select the data collection campaigns that feed into it, and the entered values populate the components without the need for re-entry. Each section is assigned to a manager or a responsible team. The report manager submits it for validation; section managers receive an email to approve or reject, and the screen displays the number of pending and completed validations for each section. In the next version, only modified sections require re-validation. Exports are available in DOCX and XLSX formats. XBRL tagging is currently under development for a release in autumn 2026.

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Breakdown by subsidiary and site

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• Harnest : you select a data point and the platform generates a sub-indicator by activity, subsidiary, or site. A group of twenty entities can break down the indicator once and track the progress of each scope.

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• Greenly does not publicly document this feature.

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What Greenly does that Harnest does not

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• ‍XBRL tagging. Greenly exports in xHTML format with XBRL tagging and integrates the European taxonomy. Harnest exports in DOCX and XLSX. If you are filing your report in ESEF format, this difference directly affects you.‍

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• Peripheral regulatory modules. CBAM, EUDR, digital product passport, EcoVadis, European taxonomy: Greenly offers a dedicated module for each topic. Harnest covers CDP and twelve other frameworks, but without these specific modules.

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• Regarding life cycle assessment, both platforms offer one. Greenly's is based on ISO standards, while Harnest's remains a simplified version based on product references.

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Hosting and artificial intelligence

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• Harnest is ISO 27001 certified and hosted in France by Scaleway. Companion, our built-in assistant, uses Mistral AI to answer questions based on your platform data. No customer data is used to train our models.

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• Greenly holds ISO 27001 and SOC 2 certifications, has completed a CNIL audit, and uses servers located in regions powered by low-carbon electricity.

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Greenly has more certifications. However, Harnest provides documentation regarding the jurisdiction of its data and language model, which Greenly does not. If ensuring your data remains under European jurisdiction is a key selection criterion, this information is available here.

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How to choose?

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You are producing your first carbon footprint report and nothing else. Greenly or another carbon-focused tool will suffice. Harnest covers these needs but also includes features you don't require at this stage.

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You are subject to CSRD and will be publishing reports annually. Harnest. Its validation workflow, data context, and reasoning traceability align with what auditors require.

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You are filing your report in ESEF format. Greenly, or Harnest supplemented by a tagging tool.

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You need to present a strategy to a board. Harnest. Strategic plans and roadmaps linked to the SDGs have no equivalent in carbon platforms.

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You are consolidating multiple subsidiaries or sites. Harnest. The generation of sub-indicators by scope and hierarchical workspaces have no equivalent in carbon platforms.

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If you already have a carbon service provider

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Emission values enter Harnest via API or import, along with their methodology and confidence level. You keep your provider and maintain a single source of truth for your non-financial data.

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Methodological note

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Information regarding Greenly is sourced from the product, pricing, and FAQ pages of greenly.earth, accessed on July 31, 2026. Information regarding Harnest is sourced from its product documentation and public pages, accessed on August 5, 2026. Any inaccuracies reported by Greenly will be corrected and dated.