After you set up your authentication method, use ping once to verify that the service is up.

curl
  -X GET
  -H 'Accept: application/json'
  -H 'Authorization: Basic aHR0cHdhdGNoOmY='
  'https://sandbox-rest.avatax.com/api/v2/utilities/ping'
                                            

You'll see a response similar to the following upon success:

{
  "version": "1.0.0.0",
  "authenticated": true,
  "authenticationType": "UsernamePassword",
  "authenticatedUserName": "TestUser",
  "authenticatedUserId": 98765,
  "authenticatedAccountId": 123456789,
  "authenticatedCompanyId": 123456789,
  "crmid": "1111"
}
                                            

Advice:
You only need to use ping once. If you want to verify periodically that the service is running, use a webhook and subscribe to status.avalara.com instead of pinging multiple times.

Ping the server