A resource from a module is missing
The browser lists adapters registered with Omeka's API adapter manager. Check that the module is installed and active, and that it registers its adapter under api_adapters in its module configuration. Reload the browser after activating a module; discovery runs on every page load.
An operation is missing for a resource
Operations are filtered by what your role may do. If Create or Delete is absent, your role does not have that privilege on the resource. Log in with a higher role or ask an administrator.
Sending a request returns 403
The request ran as your logged-in user and Omeka refused it. Choosing an API key in the credential selector does not change this: keys are only used to fill in code examples. Use an account whose role allows the operation.
Create or Update returns 422
The adapter rejected the body. The response includes an errors map naming the keys that failed validation. Compare your body with the resource's JSON-LD keys in the reference panel; most resources require o:resource_template and property values in Omeka's value format, and some require related resources to exist.
The code examples show YOUR_CREDENTIAL_HERE
Omeka displays a key's credential only once, when the key is created, and the browser cannot retrieve it later. Paste the credential you saved in place of the placeholder.
The public browser is empty
No resources are selected under Public visibility. Select at least one and save.
The OpenAPI file is out of date
The document is generated on each request from the resources discovered at that moment, so it is never cached. If a resource is missing, it is either not registered or not visible to the user downloading the spec; for the public spec, it is not ticked under Public visibility.
Is it safe to expose the public browser?
The public browser shows documentation only. It exposes resource names, parameters and schema, never data, and it cannot send requests. It does not relax the permissions on the real /api endpoints.