To test the Railz API on sandbox, first, complete the following steps.
Log into Railz Dashboard™
Enable Sandbox on the Railz Dashboard™
Create a business on the Railz Dashboard™ Sandbox Environment
Navigate to Integrations >> Accounting and enable the required accounting services.
Connect Railz Sandbox as an accounting service provider to a business created on the Railz Dashboard Sandbox Environment using Rails Sites or Railz Connect™
Here's a demo of enabling sandbox on Railz Dashboard™, connecting businesses and using the sandbox data using Railz Sites:
You may also find more details on testing Railz Connect in sandbox here.
Authentication
Even on the Railz Sandbox Environment, the users will have to first authenticate. Use the Client ID and the Client Secret to generate the access token. Please see here for more information on Authentication.
Use your Client ID and the Client Secret to generate the access token from here.
Please note that when making API calls, use 'sandbox' as the service name as Railz Sandbox is the available accounting service on the Railz Sandbox Environment.