Buyer readiness
Supply path transparency checklist
A private marketplace package is easier to trust when the commercial path, seller authorization, page placement, and final reporting fields all point to the same inventory story.
Use this checklist before a publisher package, managed demand path, or private marketplace deal goes live. It helps buyers, publishers, and operations teams inspect the supply path without turning seller transparency into a performance claim. The goal is a campaign record that can answer: who is allowed to sell this inventory, which package did the buyer activate, which placement rendered, and what reporting fields survived the flight?
What to reconcile
Supply path transparency is a join problem. The public seller file, the bid path, the deal setup, and the campaign report should not require four different stories to explain the same impression.
| Layer | Check before launch | Hold or fix when |
|---|---|---|
| Publisher domain | The public seller file is reachable from the expected root domain and matches the inventory owner or authorized manager named in the campaign brief. | The buyer is asked to accept a domain, subdomain, or managed path that does not match the package evidence. |
| Authorized seller row | The seller account, ad system domain, relationship type, and optional owner or manager fields are recorded in the launch notes. | The seller row is missing, stale, duplicated without explanation, or cannot be tied to the deal path. |
| Seller disclosure | The selling system's seller record can be checked against the account ID used in the authorized seller row. | The seller record is confidential, missing, or materially different from the campaign path without a written reason. |
| Supply chain object | The bid path shows the sequence of sellers and intermediaries expected by the buying path. | The path adds unexpected nodes, hides the final seller, or changes after launch without a change log. |
| Deal key | The private marketplace deal key maps to one package ID, eligible placement set, and reporting key. | The same deal key is used for unlike contexts or multiple package definitions. |
| Placement and report | The final report can show package ID, placement ID, device class, creative ID, seller path status, and any supply-path exception. | Delivery can only be read as a total, with no join back to the package and seller evidence. |
Preflight checklist
1. Capture the public seller state.Save the authorized seller rows that apply to the package, including ad system domain, publisher account ID, relationship type, and any owner or manager fields. Treat this as a launch record, not as proof that the campaign will work.
2. Match seller records to the account ID.Check whether the seller account used for activation appears in the selling system's seller disclosure. Record whether the seller is direct, intermediary, or confidential, and whether that status matches the buying path.
3. Write down the expected path.Before launch, name the expected seller path: direct publisher sale, managed publisher sale, reseller path, or private marketplace path through a named buying route. The report should flag delivery that does not follow that expected path.
4. Bind the deal key to a package.A private marketplace key should map to one package thesis, one included URL or topic set, one placement set, and one reporting key. If the package changes, record the date and the reason.
5. Keep exceptions visible.If a row is pending, confidential, manager-owned, reseller-only, or missing a seller disclosure, name that condition before launch. Hidden exceptions become expensive during billing, renewal, and performance review.
Read the public files carefully
The public seller files support transparency and authorization checks. They do not establish viewability, audience quality, lead quality, or incrementality.
| Evidence | What it can support | What it cannot support alone |
|---|---|---|
| ads.txt or app-ads.txt row | The publisher has declared a seller account and relationship for a domain or app context. | That the impression was viewable, high quality, or incremental. |
| sellers.json record | The selling system has published seller information connected to seller IDs, subject to its disclosure status. | That the buyer's package, page context, or creative actually matched the plan. |
| SupplyChain object | The bid request can expose the sequence of nodes involved in the transaction. | That the commercial path is the shortest, cheapest, or best-performing path. |
| Deal key | The buyer activated a named commercial path for a package or placement set. | That all delivered impressions matched the intended page context. |
| Placement ID | The report can tie delivery to a visible page slot and size family. | That the seller path was clean unless seller-path fields are also preserved. |
| Seller-path exception log | The team can explain row changes, confidential records, added intermediaries, or managed supply paths. | That the exception had no effect on delivery quality or renewal evidence. |
Reporting fields
Supply-path fields should sit beside the normal package, placement, creative, and outcome fields. They are most useful when the readout shows what was eligible, what delivered, and what could not be verified.
| Field | Definition | Use in readout |
|---|---|---|
| supply_path_status | Expected, changed, pending, confidential, unmanaged, or not checked. | Shows whether delivery followed the path agreed before launch. |
| seller_relationship | Direct, reseller, intermediary, managed, or unknown. | Separates direct publisher supply from managed or reseller paths. |
| seller_account_id | The seller account used in public authorization and activation records. | Lets ad operations reconcile seller files, deal setup, and invoice records. |
| ad_system_domain | The advertising system domain declared for the seller account. | Connects public seller authorization to the system where buying occurred. |
| schain_node_count | The number of nodes visible in the supply chain record when available. | Helps flag unexpected path length changes before renewal language is written. |
| seller_path_exception | A short explanation for missing, confidential, changed, or unexpected seller-path evidence. | Keeps unresolved transparency questions out of performance claims. |
| package_id | The contextual package sold to the buyer. | Connects seller-path checks to the reader context being purchased. |
| placement_id | The visible ad slot or placement contract where the unit rendered. | Prevents seller-path review from floating above page-level delivery evidence. |
Decision bands
| Status | Use when | Next action |
|---|---|---|
| Ready for package activation | Authorized seller rows, seller records, expected path, deal key, package ID, and report fields align. | Launch with the seller-path fields included in the campaign export. |
| Ready after operations fix | The package and inventory are sound, but one seller row, seller record, or deal mapping needs correction. | Fix before launch, then document the correction in the campaign handoff. |
| Report with exception | Delivery can run, but a seller record is confidential, pending, or routed through a managed path. | Name the exception and keep performance language descriptive. |
| Hold for path review | The seller path cannot be tied to the package, placement, or deal key. | Do not sell or renew the package as a clean private marketplace lane until the path is rebuilt. |
Official references
Use official technical references to define the transparency fields, then use the campaign's own records to judge whether a specific package was ready. The IAB Tech Lab ads.txt reference explains authorized seller declarations, the IAB Tech Lab sellers.json and SupplyChain reference explains seller disclosure and supply chain visibility, and the source library groups these references with other measurement and inventory checks.
Pair with
Use this checklist with the programmatic inventory QA checklist for placement and size-map checks, the ad yield and deal-readiness checklist before pricing, the private marketplace reporting field dictionary for package and placement fields, the private marketplace readout export sample for row-level checks, and the ad inventory readiness matrix for the current package contracts.
Takeaway
A transparent supply path is not a performance result. It is a necessary record that lets buyers and publishers know which inventory was authorized, how it moved, where it rendered, and how much confidence the final report deserves.