> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tesouro.com/llms.txt
> Use this file to discover all available pages before exploring further.

# HTTP headers

> Learn about HTTP headers that can be passed in request and responses when interacting with Tesouro API.

## Request headers

### Authorization

Contains a bearer token (of a partner or organization user) to authorize this API request. For more information, see [Authentication](/finops/guides/authentication/overview).

### x-tesouro-version

Specifies a Tesouro API version to process this API request. For more information, see [Tesouro API versioning](/finops/api/concepts/versioning).

### x-organization-id

Specifies the unique ID of an organization, which is the owner of the API resource of a collection of resources. This is an additional security mechanism that allows to ensure the [Tesouro account structure](/finops/guides).

## Response headers

### x-tesouro-version

Returns back the Tesouro API version that was used to process this API request.

### x-request-id

Contains a random ID generated by Tesouro to uniquely identify this API response. Always provide this ID when reporting any issues to the [Tesouro Support Team](/finops/support).

### x-process-time

Contains a value specifying the time spent on processing the original API request.

### x-organization-id

Returns back the organization ID specified in the original API request.