# Call the API

Communications Cloud TM Forum APIs use the following URL format:

```
<Domain name>/<TMF API>/<API version>/<Resource type>
```

where

- **Domain name**:
  - **For US region in the Production environment** - api.commscloud.salesforce.com
  - **For US region in the Sandbox environment** - api.commscloud.salesforce.com/sandBox/
  - **For EU region in the Production environment** - eu.api.commscloud.salesforce.com
  - **For EU region in the Sandbox environment** - eu.api.commscloud.salesforce.com/sandBox/
- **TMF API** - Code of the TMF API
- **API version** - TMF API version
- **Resource type** - TMF resource type

The URL format in this topic applies to Mule Gateway access. For Direct Access (Connect/Apex REST) sample URLs and payloads, refer the respective TMF API use cases.
To improve performance of OmniStudio-based APIs, [disable unused optional fields](/docs/industries/communications/guide/disabling_fields.md) in the DataRaptor.