The 7 best Scope 3 supplier engagement software platforms in 2026

Supplier engagement software promises to turn a supplier list into Scope 3 data. Seven platforms come up on procurement and sustainability shortlists for the job, and they answer three different questions: what will suppliers tell me if I ask, how do my suppliers score, and what do I already know before I ask anyone. This page ranks them on the question that decides a programme's ceiling: what you get for the suppliers who do not reply.

Platform list updated 22 September 2026. Verification status from our benchmark, evidence links last checked 19 August 2026.

How should you compare supplier engagement software?

Compare on what happens before, during and after a request, in that order.

• Before: how much of your supplier list already carries an emissions figure before a single request goes out. On most platforms the answer is none, because the data arrives by collection. On a platform with a company emissions layer underneath, most of the list is covered from day one and the request goes only where a better figure would change the total.
• During: what the request asks of the supplier. A blank portal asks a one or two person sustainability team to compile an inventory for you, and every buyer running its own programme asks them the same questions in a slightly different order. A request prepopulated with what the supplier has already published asks them to review and correct, which is a different amount of work.
• After: what you get when nobody replies. Most of a supplier list will not respond to a cold survey in the first cycle. A survey tool returns nothing for those rows. A data-first tool returns the supplier's published figure where one exists and a sector average where it does not, shown as such, so the inventory closes and the gap is visible.

Three more things separate the seven: who pays for the supplier's answer, whether the output is a tonnage that can enter an inventory or a score that cannot, and whether the calculation methodology has been verified by a named third party against a standard.

Who pays for the supplier's answer?

On several of these platforms, the supplier does. EcoVadis charges the supplier for its rating. CDP charges a disclosure fee to the companies that respond. Manufacture 2030 charges suppliers a subscription to join and report. The buyer's request therefore arrives with an invoice attached, which is a reason not to answer it, and the suppliers least able to pay are the small private ones that make up the tail of every list. On DitchCarbon a supplier claims its profile, answers and shares data for nothing, because the buyer is the customer and the supplier is the one being asked. A supplier's answer costs them their time; it should not also cost them a fee.

How big is the supplier engagement software market?

There is no independent market-size figure we are prepared to cite, and the vendor-commissioned ones describe different categories (supplier risk, ESG ratings, carbon accounting, procurement suites) under the same label, so they cannot be added up. The size that matters to a buyer is smaller and measurable: how many of your suppliers already have a published emissions figure, and how many of the rest will answer a request. The first number is the coverage you start with. The second is the ceiling on everything a survey-led tool can do. Ask any vendor for both on a sample of your own list before you compare prices.

The 7 best Scope 3 supplier engagement software platforms in 2026

Ranked by fit for supplier-level Scope 3 work: coverage before anyone is asked, burden on the supplier, what comes back for non-responders, and verification of the methodology.

1. DitchCarbon

DitchCarbon starts from verified emissions data for over 2 million organisations, built on primary emissions data wherever it exists, so most of a supplier list carries a company-specific figure before a request is sent. The four-step maturity ladder sorts suppliers against embodied emissions, from not disclosing through to leading with product carbon footprints, so the requests go to the organisations where a primary figure would change your Category 1 total rather than to everyone. Each request arrives prepopulated with what that organisation has already published, so the supplier reviews and corrects rather than compiles, which gets a higher response rate than a cold survey. A supplier answers once on its own profile, and any logged-in viewer from another organisation reads the same answer; the survey responder lets a supplier forward a buyer's questionnaire by email and have it answered from profile data. Claiming a profile, answering and sharing data is free for the supplier; the buyer is the customer. Where nothing has been disclosed and nothing comes back, the sector average holds the line and is shown as such. Every figure carries its source and change history, and the Portal calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually. A recent deployment reached about 60% of a large supplier base within 2 weeks.

What you still need afterwards: nothing for the baseline, or for assured emissions calculations. Requests are for the gaps.

2. EcoVadis

EcoVadis rates a supplier's sustainability management on a scorecard once the supplier has completed an assessment and paid EcoVadis for its rating, and a Carbon Action Module adds carbon maturity questions. Your request to a supplier is a request that they buy a rating. What comes back is a score out of 100, which is a rating of practices rather than a tonnage, so it cannot enter a Scope 3 inventory; a supplier that has not completed an assessment has no scorecard, and the scorecards you do hold describe the suppliers who chose to be rated. If you already hold EcoVadis scorecards, DitchCarbon turns them into structured emissions data and matches each to the supplier's own published inventory. We checked EcoVadis for our verification benchmark and found no public software-level verification of a calculation methodology.

What you still need afterwards: the tonnes. A score out of 100 cannot enter an inventory, and only the suppliers who paid for a rating have one.

3. IntegrityNext

IntegrityNext screens suppliers across ESG and compliance risk topics during sourcing and onboarding, with carbon questions carried alongside the risk view. A supplier receives a questionnaire and the platform records what it returns, so coverage is the response rate, and the output is a risk profile with a carbon self-declaration inside it rather than a calculated Category 1 line. DitchCarbon supplies the figure for each supplier from what it has published, and the risk screen can sit alongside it. IntegrityNext is not in our verification benchmark.

What you still need afterwards: a Category 1 figure. A risk flag is not a calculation, and it does not move when a supplier cuts emissions.

4. CDP Supply Chain

CDP Supply Chain lets a member ask its suppliers to complete the CDP climate questionnaire, and returns the disclosure and an A to D score for the suppliers who do. The questionnaire is the full corporate disclosure and CDP charges the responding company a disclosure fee, so the suppliers most likely to complete it are the large, already-disclosing ones with a budget for it, and a supplier that does not respond leaves an empty row. For the suppliers who do respond, the disclosure is the same primary data DitchCarbon reads from the public record, so a CDP response is an input to a DitchCarbon figure rather than an alternative to it, and a supplier who has already answered CDP can reuse that answer on their DitchCarbon profile. CDP is not in our verification benchmark.

What you still need afterwards: the non-responders, who include everyone unwilling to pay the disclosure fee, and the allocation. A CDP disclosure is an input to your Category 1 line, not the line.

5. Sphera SCS (formerly SupplyShift)

Sphera SCS distributes supplier assessments, collects the responses and scores them, and sits inside Sphera's wider EHS and sustainability suite. The data model is the survey: a supplier's figure exists once that supplier has filled in the assessment, and the platform holds no emissions figure for a supplier that has not. We checked Sphera SCS for our verification benchmark and found no public software-level verification. DitchCarbon holds the supplier's published figure before any assessment is sent, and sends a request only where that figure needs improving.

What you still need afterwards: everyone who did not fill in the assessment. The response rate is the ceiling of the whole programme.

6. Manufacture 2030

Manufacture 2030 runs a platform that suppliers join to report their emissions and reduction plans to the buyers who are members, with the suppliers' own progress tracked over time. Suppliers pay a subscription to join. It works where a supplier has joined and reports; a supplier that has not paid to join is not in the data, so coverage is the share of your list that has signed up and kept paying. We checked Manufacture 2030 for our verification benchmark and found no public software-level verification. DitchCarbon covers the suppliers that have not joined anything from what they have published, and tracks each organisation's forecast against its own target trajectory.

What you still need afterwards: the suppliers who never paid to join. Membership is the coverage, and most of a list is not a member.

7. Sweep

Sweep is a full-inventory carbon accounting platform with a supplier survey module: buyers send surveys, suppliers return data, and the returned data feeds the Category 1 calculation, with a spend-based fallback for the suppliers who do not respond. The supplier module is a feature of the system of record rather than the product. Run alongside Sweep, DitchCarbon becomes the supplier data layer feeding it, so the spend-based fallback is replaced by the supplier's own published figure and the survey goes only to the gaps. We checked Sweep for our verification benchmark and found no public software-level verification of its calculation methodology.

What you still need afterwards: the supplier data itself. Without it the Category 1 total is a sector average with a reporting layer on top.

Verification status from our benchmark, Who's Really Verified? A Reality Check on Carbon Software Assurance, evidence links last checked 19 August 2026. "Not in our benchmark" means we have not checked that vendor and nothing should be read into it. Other columns reflect each vendor's public product documentation.

What does a survey actually cost?

Not your licence. The hours, and not only yours, and on three of these platforms a fee the supplier pays. A supplier's sustainability team is usually one or two people, and every buyer running its own programme asks them the same questions in a slightly different order. Time spent on the fifteenth version of the same form is time not spent cutting emissions. Any model that has to ask every supplier before it knows anything adds to that queue, whoever is running it.

The survey also works best where it was least needed. Large, engaged, already-disclosing suppliers answer, and their figures were in the public record anyway. Down the tail, a cold request is unpaid work for a company with no reason to prioritise it, and the tail is where the coverage gap is. That is why the order matters: coverage that exists before anyone is asked, then a prepopulated request where a figure needs improving, then a sector average shown as such where nothing comes back. On DitchCarbon that order is the product, and the maturity ladder is what decides who is worth asking.

What happens after the data comes back?

A supplier figure nobody acts on is an expensive spreadsheet. On DitchCarbon each organisation is forecast against its own target trajectory, and the forecast aggregates to category and account level so you can see where a whole category lands as well as any one supplier in it. Targets are tracked with SBTi-validated separated from self-declared. Reduction recommendations are ranked by tonnes and carry a named peer. The 0 to 100 score breaks down by criterion, so filtering to the criteria a supplier has not earned turns a scorecard into an engagement list. The forecast is projection rather than measurement and carries a reliability notice where the underlying disclosure is patchy; the ISO 14064-3 verification covers the calculator, not the forecast.

If you are the supplier being asked

If you are reading this because a customer sent you one of these requests, the fastest answer is the data you have already published. Claim your organisation's profile, check what is already held against your name, answer the questions buyers ask most often once, and choose who can read the answers. Forward the next questionnaire to the survey responder and it is answered from the same profile, instead of the fifteenth version of the same form. It costs you nothing.

The short version

Supplier engagement software is sold as the way to get Scope 3 data. On six of the seven platforms here the data arrives by asking, so the response rate is the ceiling and the suppliers who do not reply are a blank, and on three of them the supplier pays to reply. DitchCarbon starts from what over 2 million organisations have already published, asks only where a primary figure would change the total, charges the supplier nothing to answer, and shows the sector average where nothing better exists rather than hiding it.