The following request headers are common to all tasks that you might do with the DocumentDB API:
| Header | Required | Type | Description |
|---|---|---|---|
| Authorization | Required | String | The authorization token for the request. For more information on generating a valid authorization token, see Access Control on Cosmos DB Resources |
| Content-Type | Required (on PUT and POST) | String | For POST on query operations, it must be application/query+json. For attachments, must be set to the Mime type of the attachment. For more information on Mime types, see Create an Attachment For all other tasks, must be application/json. |
| If-Match | Optional (applicable only on PUT and DELETE) | String | Used to make operation conditional for optimistic concurrency. The value should be the etag value of the resource. |
| If-None-Match | Optional (applicable only on GET) | String | Makes operation conditional to only execute if the resource has changed. The value should be the etag of the resource. |
| If-Modified-Since | Optional (applicable only on GET) | Date | Returns etag of resource modified after specified date in RFC 1123 format. Ignored when If-None-Match is specified |
| User-Agent | Optional | String | A string that specifies the client user agent performing the request. The recommended format is {user agent name}/{version}. For example, the official DocumentDB API .NET SDK sets the User-Agent string to Microsoft.Document.Client/1.0.0.0. A custom user-agent could be something like ContosoMarketingApp/1.0.0. |
| x-ms-activity-id | Optional | String | A client supplied identifier for the operation, which is echoed in the server response. The recommended value is a unique identifier. |
| x-ms-consistency-level | Optional | String | The consistency level override for read options against documents and attachments. The valid values are: Strong, Bounded, Session, or Eventual (in order of strongest to weakest). The override must be the same or weaker than the account’s configured consistency level. |
| x-ms-continuation | Optional | String | A string token returned for queries and read-feed operations if there are more results to be read. Clients can retrieve the next page of results by resubmitting the request with the x-ms-continuation request header set to this value. |
| x-ms-date | Required | Date | The date of the request per RFC 1123 date format expressed in Coordinated Universal Time, for example, Fri, 08 Apr 2015 03:52:31 GMT. |
| x-ms-max-item-count | Optional | Number | An integer indicating the maximum number of items to be returned per page. An x-ms-max-item-count of -1 can be specified to let the service determine the optimal item count. This is the recommended configuration value for x-ms-max-item-count |
| x-ms-documentdb-partitionkey | Optional | Array | The partition key value for the requested document or attachment operation. Required for operations against documents and attachments when the collection definition includes a partition key definition. Supported in API versions 2015-12-16 and newer. Currently, Azure Cosmos DB supports a single partition key, so this is an array containing just one value. |
| x-ms-session-token | Required (for session consistency only) | String | A string token used with session level consistency. For more information, see Using consistency levels in Cosmos DB |
| x-ms-version | Required | String | The version of the Cosmos DB REST service. For a list of supported API versions, see Azure Cosmos DB REST API Reference |