Rejecting unclear marketplace software candidates before anyone scores them

Use this marketplace seller software selection checklist before scoring a candidate. It is an evidence-gap gate for one fictional England seller, not a compliance certificate or product recommendation. Mark each line PASS, FAIL, UNRESOLVED or NOT TESTED and attach the evidence ID.

Research closed on 6 September 2026. Buyer weights, thresholds and prices remain blank.

Identify the subject

• Legal supplier, trading name and contract party match current evidence.
• Exact UK-available service and edition are named.
• The authorised marketplace account and permitted functions are documented.
• Included product, stock and order states have explicit exclusions.
• First-party service and technical records carry access dates and versions.

Companies House guidance on searching the register supports narrow identity checks. Do not interpret registration as quality, solvency, permission or fitness.

Attach the source document and access date to every PASS. A supplier statement can support only the claim it actually makes for that edition and territory. Where the account permission, contract party or service boundary cannot be verified, stop before requesting credentials or uploading a fixture.

Check the customer and product route

• Approved product identifiers and evidence remain traceable through transformations.
• The buyer can inspect the rendered seller identity, description, total price and genuine optional choices.
• Order placement, acceptance, authorisation, capture, fulfilment, cancellation, return, refund, dispute and settlement remain separate.
• Safety evidence, suppression, correction and withdrawal have named owners.

GOV.UK online-selling guidance identifies information, price and ordering matters. OPSS product-safety advice explains why the product and business role matter. Qualified reviewers decide applicability.

Inspect data, access and assurance

• Controller, processor or other role analysis is recorded for each data flow.
• Purposes, instructions, device access, subprocessors, transfers and retention are evidenced.
• Privileged access is least-privilege, logged, reviewable and revocable.
• Incident notification, containment and recovery evidence have owners.
• Staff and customer tasks have an accessibility method and unresolved-defect route.

The ICO's controller-processor contract guidance is under DUAA review. NCSC supplier-assurance questions cover security and recovery topics. Neither source verifies a candidate.

Where the test involves storage or access on user equipment, map that action separately. The ICO's storage and access technologies guidance gives the current PECR context but does not validate the candidate's configuration.

Normalise commercial evidence

• Currency, VAT basis, charging unit, billing period, term, limits and refund conditions are stated, or the field is UNKNOWN.
• Supplier charges are separated from marketplace, payment, implementation, labour, support and exit costs.
• Contract change, suspension, liability, insurance and audit fields are assigned to qualified reviewers.
• Tax and accounting treatment has an accountant-owned hold.

Do not enter a price from another edition, territory or promotional period.

Record support as a defined contact route, event and evidence requirement. Leave response and availability thresholds blank unless the exact reviewed contract supplies them. A public help page does not establish contracted assistance or recovery time for this seller.

Require reversible testing and exit

• The shared fictional fixture has predeclared expected results.
• No live listing, payment, customer message or personal data is used.
• Duplicate, late, rejected and corrected events are retained in the evidence.
• Rollback, credential revocation, export, deletion and isolated restore are demonstrated.
• Production stays disabled until every non-compensating gate passes.

A checklist total is not a verdict. Reject or hold a candidate when identity, account authority, consumer, safety, privacy, accessibility, security, tax, contract or exit evidence is missing. Only a named reviewer can issue a bounded pilot decision for the exact edition and tested configuration.

Record the decision

The final line names the decision owner, verdict, failed or unresolved gates, evidence versions and expiry. It also states what new proof can reopen the review and who can keep production disabled. Preserve rejected evidence and rerun history so a later team can understand why the candidate stopped.