An Atlassian Cloud organization can have one or more sites, each containing one instance of each product1. A site has its own URL and administration settings2. Since your organization has two instances of Jira Software and two instances of Confluence, it must have at least two sites to host them. For example, one site could have the URL acme.atlassian.net and contain Jira Software and Confluence, while another site could have the URL acme-dev.atlassian.net and contain another instance of Jira Software and Confluence.
The other options are not necessarily true for your organization. Having multiple sites does not imply that you have verified your domain, which is a process that allows you to manage the Atlassian accounts of your users and apply security policies to them3. You may or may not have verified your domain, depending on whether you have access to your domain’s DNS or HTTPS settings. Verifying your domain is not required to use Atlassian cloud products.
A landing product is the product that your users see first when they log in to your site4. You can only set the landing product to Jira or Confluence. Therefore, you cannot have exactly four landing products, as you can only have one landing product per site. You may have two landing products if you set one for each site, or you may have none if you do not set any.
A Premium subscription plan is a plan that offers advanced features, unlimited storage, 99.9% uptime SLA, and 24/7 Premium support for Jira Software, Confluence, Jira Service Management, and Jira Work Management5. You may or may not have a Premium subscription plan for your products, depending on your needs and budget. Having multiple sites or products does not automatically mean that you have a Premium subscription plan.
A sandbox is an isolated environment where you can test and experiment before making changes to production6. A sandbox is available for Jira Software, Jira Service Management, and Confluence with Premium and Enterprise plans6. You may or may not have sandboxes for your products, depending on whether you have a Premium or Enterpriseplan and whether you have created a sandbox from your organization. Having multiple sites or products does not automatically mean that you have sandboxes.
References :
Understand Atlassian sites and organizations
What is an Atlassian organization?
Verify a domain to manage accounts
Set your site’s landing product
Atlassian Cloud Premium
Manage product sandboxes
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