Firebase Auth Emulator email/password Sign In REST endpoint

I'm able to use this endpoint https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key=[API-KEY] (found in these docs @ section Sign In With Email / Password) to sign in a Firebase Authentication user via an HTTP request.

Is there anyway to accomplish this on the Firebase Authentication Emulator - is there an emulator REST endpoint which will serve the same function?

When I run the auth emulator on port 9099 I've tried -
. http://localhost:9099/v1/accounts:signInWithPassword?key=[API-KEY]
. http://localhost:9099/emulator/v1/accounts:signInWithPassword?key=[API-KEY]
. http://identitytoolkit.localhost:9099/emulator/v1/accounts:signInWithPassword?key=[API-KEY]
. http://localhost:9099/identitytoolkit/v3/relyingparty/verifyPassword?key=[API-KEY]

But none work. Any ideas?

Here is the response I get for each of these requests -

{
    "error": {
        "code": 404,
        "message": "Not Found",
        "errors": [
            {
                "message": "Not Found",
                "reason": "notFound"
            }
        ],
        "status": "NOT_FOUND"
    }
}

EDIT: Also tried this: http://localhost:9099/identitytoolkit.googleapis.com/v1/projects/emulator-test-project-id/accounts?key=[API-KEY]

but get the response

{
    "error": {
        "code": 400,
        "message": "INSUFFICIENT_PERMISSION : Only authenticated requests can specify target_project_id.",
        "errors": [
            {
                "message": "INSUFFICIENT_PERMISSION : Only authenticated requests can specify target_project_id.",
                "reason": "invalid",
                "domain": "global"
            }
        ]
    }
}