How do I connect publisher inventory so advertising agents can discover it?

A publisher makes its inventory discoverable to advertising agents by signing up for an Apostra Seller Account, connecting its ad server as an inventory source, adding its products, and authorizing Apostra to sell for its domains in its adagents.json file. After Apostra’s review, buyers and their agents on Apostra can find the storefront, buy a product outright, or send a brief and get a plan back. You set the prices and rules. A buyer on Apostra can buy only from sellers that are listed on Apostra, whether through a Storefront Apostra hosts or a sales agent you bring.

Choose how you sell

	Listing	Storefront	Your own AdCP sales agent, no Apostra
Who answers buyers	Your own sales agent, or a third party’s	A storefront agent Apostra hosts	Your own agent
Who finds you	Buyers on Apostra	Buyers on Apostra	Whoever you reach on your own
Charge from Apostra	None	Per Intelligence Unit (IU), Apostra’s billing unit, on the metered activities. See the Rate Card	None
Share of your media	0%	0%	Not applicable

If you run your own sales agent, AdCP’s own guide, Making your inventory available to AI agents, covers publishing adagents.json and brand.json and implementing get_products, create_media_buy and get_media_buy_delivery. Apostra builds on the same protocol, so you can follow that guide and still list on Apostra. Prices are in What you pay as a seller, and the live Rate Card is the authority. See Building on Apostra or on AdCP directly if you are deciding whether to bring an agent at all.

What each step needs

Step	What you do	Access it needs
Sign up	Create the account at app.apostra.com/signup?intent=storefront	A work email on your company’s domain. A personal webmail address is not accepted
Connect an ad server	Call `save_inventory_source` with `{"adServer":{"type":"google_ad_manager"}}`, or `freewheel`, `springserve`, `adswizz`, `broadsign` or `citrusad`. It opens a connection form	Ad-server credentials, entered in the form. They never pass through chat or a tool call
Give Apostra access in Google Ad Manager	Add the service account email that Apostra creates for your organization as a user in your network	Someone in GAM who can add a service account user and give it a role. Apostra recommends the built-in Administrator role. Trafficker cannot approve orders and does not work
Authorize the sales agent	The publisher adds one entry to its `adagents.json`. Apostra reads that file for each publisher domain, and falls back to a `MANAGERDOMAIN` line in `ads.txt` only when the publisher’s own file returns 404	Whoever edits the publisher’s file. See Publisher adagents.json entry
Add seller materials	Register a media kit, deck, rate card, site or instructions with `save_material`	An upload follows prepare, upload and finalize. An uploaded rate card is evidence, not approval to change published prices
Test	Run a sandbox booking against your own supply to verify the path without spending	A Seller Account

Sellers that sell through an ad platform such as Meta or TikTok have no adagents.json step. Their selling rights come from the platform account. After you finish setup, Apostra does some work before buyers outside your organization can find you. Apostra publishes no timings for that step. The whole path, with an example, is in From signup to your first booking.

Limits to check

A configured connection is not proof of a live call. get returns recorded state and does not probe your ad server.
Configuring an inventory source does not publish it or satisfy live campaign readiness.
Publisher authorization does not prevent transactions. It lets buyers verify that the publisher authorized your storefront. The setup step stays open until every declared domain is authorized.
Seller delivery is seller-reported. It is not buyer measurement and does not establish billing eligibility by itself.
Real-time targeting with Prebid and Google Ad Manager is a separate setup. See Set up TMP with Prebid. Connecting an inventory source does not install it.
Some credential, payout, approval and reassignment work stays in the web app rather than in tools a model calls.

When not to use Apostra

You already run an AdCP sales agent and need nothing from Apostra’s buyers, testing or certification. AdCP is open. You can run your agent anywhere.
You need to be sold through channels Apostra does not connect. A listing makes you discoverable to buyers on Apostra, not elsewhere.
Your ad server is not on the supported list. A sales agent is added only as one of your organization’s agents or a certified partner’s, never from an endpoint alone. See Connect to a partner agent.

Next step

Sign up at app.apostra.com/signup?intent=storefront, then follow From signup to your first booking. To drive the steps with a coding agent, install the developer plugin from Connect in five minutes, call get_status from your Seller Account, then start the ad-server connection:

{ "adServer": { "type": "google_ad_manager" } }

Send that as the input to save_inventory_source. It creates nothing and opens the Connect ad server form.

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