How we review marketplace seller software, from fictional fixture to limited verdict

A marketplace seller software review methodology must make absence visible. On 6 September 2026, no exact supplier, service edition or complete first-party dossier was submitted for this fictional England seller. No service was configured or tested. The present verdict is NOT ADMITTED, not a negative judgement about unnamed suppliers.

Hands-on actions performed: none. Not tested: marketplace access, configuration, product transmission, orders, payments, refunds, support, security, accessibility, export and recovery.

Publish who reviewed what

The buyer-side marketplace reviewer is to be assigned. The future record must name that person, competence, employer or client relationship and independence. It must identify the legal supplier, trading name, exact service and edition, UK availability, authorised marketplace account and bounded product-stock-to-order job.

Companies House guidance on searching the company register describes accessible company information. Use it to verify narrow register facts. It cannot prove that a service exists as described, supports an account or is suitable.

Record the review date, document dates, funding, affiliate interests, free access or samples. This article received none. Set recheck triggers for an entity, edition, contract, interface or permission change.

Apply an evidence hierarchy

Start with current first-party service, technical, contract, privacy, security, accessibility, support and exit records for the exact edition. Separate those supplier claims from company-register facts, signed contract evidence, independent authority material and controlled observations. Customer comments may prompt questions, but they do not replace a reproducible test.

NCSC supplier-assurance questions cover governance, incidents, access, data and contract subjects. Answers need dated supporting evidence; completing a questionnaire is not a security verdict.

Create an evidence ledger with one row for the claim, publisher, exact page or document, edition, geography, access date, scope and expiry trigger. Attach a second row for the buyer's verification. If the claim concerns marketplace access, the verification must identify the buyer's account and permission rather than rely on a public directory. If a contract or technical record is unavailable, label the criterion UNKNOWN and stop admission.

Run a common fictional fixture

Only an admitted candidate receives the buyer-controlled test. Production remains disabled. Use fictional product and order identifiers to exercise approved and rejected product changes, conflicting stock, corrected total price, optional choice, duplicate or late events, cancellation, partial refund, dispute, suppression, tracking refusal, access revocation, rollback, export, deletion and isolated restore.

The test log states configuration, expected result, observed evidence and reviewer. No live listing, payment, customer message, personal data, marketplace support case, load test, penetration test or long-term operation is implied.

Repeat failed actions only under a written rule. Preserve the initial result, changed configuration and rerun outcome. Otherwise a clean rerun can hide the route that a real operator would have encountered. Capture screenshots only when authorised and retain machine-readable event evidence where the test depends on timing or state order.

Keep independent gates

GOV.UK online-selling guidance identifies information, price, ordering and confirmation subjects. OPSS product-safety advice ties safety responsibilities to the product and business role. The ICO's controller-processor contract guidance is under DUAA review and identifies data-contract questions. Each source informs a separate specialist gate; none certifies software.

Accessibility, tax, security, consumer presentation, privacy and exit cannot be averaged into a feature score. Buyer weights and thresholds stay blank. One failed gate can require HOLD regardless of other results.

Limit the verdict

Allowed outcomes are NOT ADMITTED, UNTESTED, HOLD, SUITABLE FOR A DEFINED PILOT or REJECT against a predeclared requirement. State untested areas and evidence expiry beside the outcome. Because this method had neither a candidate dossier nor controlled observations, NOT ADMITTED is the only supported verdict today.

The verdict record must show who can change it and what new proof is required. A later supplier response does not silently overwrite the review; it opens a dated reassessment for that exact edition and account context.