Join the use case
Do this once per care organization, per use case: register on the use case's Discovery Service so other parties can find you.

Register on the Discovery Service
Register the care organization on the use case's Discovery Service, so other parties can find it and its API endpoints. In the Nuts node this is called "activating" the Discovery Service for a subject.
Do this once per care organization, per use case. The node then keeps the registration up to date by itself.
Before you start
The node has the use case's Discovery Service definition (see chapter "Configure the node for a use case").
The care organization has a subject (see "Create a subject").
The wallet has the credentials the Discovery Service definition requires (see "Load the credential into the wallet").
You know which registration parameters the use case requires, see below.
Registration parameters
Registration parameters are values you publish with the registration, typically API endpoints. The use case says which ones you need. The node puts them in a DiscoveryRegistrationCredential, so you don't need to issue that credential yourself.
The node always adds 
authServerURL: your Nuts node's OAuth2 authorization server URL for this subject.
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The wallet only needs the X509Credential. Registration parameters:
Parameter
Required
Value
fhirR4BaseURL
At least one of the two
Base URL of your FHIR R4 API
fhirStu3BaseURL
At least one of the two
Base URL of your FHIR STU3 API
The service ID is 
360-graden.
Using the API
POST <internal Nuts interface>/internal/discovery/v1/<service ID>/<subject ID>
Content-Type: application/json
{
  "registrationParameters": {
    "<parameter>": "<value>"
  }
}
<service ID> is the 
id field of the Discovery Service definition.
<subject ID> is the care organization's subject ID, e.g. 
careorg-a-acc.
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POST <internal Nuts interface>/internal/discovery/v1/360-graden/careorg-a-acc
Content-Type: application/json
{
  "registrationParameters": {
    "fhirR4BaseURL": "https://fhir.example.com/r4"
  }
}
The node registers right away:
Response
Meaning
What to do
200 OK
Registered. The node refreshes the registration by itself before it expires.
Nothing
412 Precondition Failed
Not registered. The response says why, e.g. missing credentials or the Discovery Server can't be reached. The node does not retry by itself.
Fix the cause and call the API again
404 Not Found
Unknown service ID or subject ID
Check both IDs
Check that it worked
Get the registration status:
GET <internal Nuts interface>/internal/discovery/v1/<service ID>/<subject ID>
activated should be 
true and 
status should be 
active.
If 
status is 
error, 
error says what went wrong, e.g. a refresh that failed.
Then check that others can find you, by searching for your own care organization, e.g. by name:
GET <internal Nuts interface>/internal/discovery/v1/<service ID>?<path in the credential>=<value>
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The name is in the X509Credential:
GET <internal Nuts interface>/internal/discovery/v1/360-graden?credentialSubject.subject.O=Zorgorganisatie%20A*
The query parameter is a path in the credential (without 
$.), not a field ID from the definition.
Matching is case-insensitive, and 
* is a wildcard at the start or end.
Your care organization should be in the result, with your DID in 
credential_subject_id and your registration parameters in 
registrationParameters.
See "Find care organizations and their endpoints" for more search options.
Changing or removing the registration
Change the registration parameters, e.g. a new FHIR URL: call the 
POST again with the new values.
Remove the registration:
DELETE <internal Nuts interface>/internal/discovery/v1/<service ID>/<subject ID>
200 OK means it was removed. 
202 Accepted means the node stopped refreshing, but couldn't remove the registration from the Discovery Server; it disappears there when it expires.
API reference: Discovery Service