# Payloads

SVAML (Sinch Voice API Markup Language) is a JSON-based markup language used to define call flows and control the behavior of voice calls in the Sinch Voice API. It allows developers to specify commands that dictate how calls are handled, including dialing, playing messages, gathering input, and more.

SVAML is used in various contexts within the Voice API, including:
- **Call Creation**: When initiating outbound calls via the API.
- **Webhooks**: When responding to call events with commands to control the ongoing call flow.
- **Batch Calls**: When defining call flows for multiple calls in a batch operation.

## Describe the call flow from the SVAML payload

 - [POST /v2/projects/{projectId}/svaml/describe](https://developers.sinch.com/docs/voice-2.0/api-reference/voice/payloads/describesvaml.md): This endpoint is useful for understanding the structure and flow of a SVAML payload without executing it. It provides a detailed description of the commands, events, and messages defined in the SVAML.

## Validate a SVAML payload

 - [POST /v2/projects/{projectId}/svaml/validate](https://developers.sinch.com/docs/voice-2.0/api-reference/voice/payloads/validatesvaml.md): This endpoint checks the structure and content of the SVAML commands to ensure they conform to the expected schema and rules. It can operate in different validation modes, such as strict or lenient, depending on the requirements.