Discovery: what data is out there?

A data space has no central marketplace. Every company publishes its own catalog and stays the only authority on what it offers.

The idea

To find data, your connector asks the other companies directly, using the Dataspace Protocol, and combines their answers. This is called federated discovery.

A federated search is a set of direct requests. Each catalog answers for itself. Bob's research dataset shows up too: being listed is not the same as being allowed.

A catalog entry tells others that a dataset exists and under which policy it is offered. It does not give access. That decision comes later, during negotiation.

Try it

For the rest of the route you act as Alice, using Alice's Dataspace Starter: the app a company uses to browse catalogs and request data.

1. Open Alice's Dataspace Starter and log in.
2. Open Own Catalog. This is what Alice publishes: Alice HTTPBin.
3. Open Federated Search and search for httpbin. The results come from the other companies' catalogs, not from a central index.
4. Open Browse Participant and pick Bob's participant (its DID ends in tenants:bob). Bob's catalog lists Bob Research HTTPBin, even though Alice isn't allowed to use it.

The other sections in the Dataspace Starter menu

Section	What it does
Own Catalog	Datasets this company publishes
Federated Search	Search across the catalogs of every known participant
Browse Participant	One participant's full catalog
Datasets / Versioned datasets / Collections	Manage this company's own published datasets
Transfers	Running and past data exchanges
Tester	Negotiate a contract and fetch data in one action. You will use it in step 3.

What to remember

Catalogs are visible to every member, access is not. Alice can see Bob's research dataset and read its policy. Whether Alice can actually use it depends on the credentials Alice holds.

Alice knows which datasets exist. Next, she tries to get one, and then tries one she isn't entitled to.

Next: 3. Data exchange