Response Headers

Each response from Vault API includes read-only response headers. These headers contain various metrics to aid developers in monitoring performance, limits, and more.

The following headers are returned for all Vault API calls unless otherwise noted:

Response Header Name	Description
`X-VaultAPI-ExecutionId`	The unique ID associated with this API request. Include this value with any Support ticket regarding the Vault API.
`X-VaultAPI-BurstLimit`	The maximum number of calls allowed in a burst window before throttling is enforced. Learn more about API rate limit headers.
`X-VaultAPI-BurstLimitRemaining`	The number of API calls remaining for the current 5-minute burst window. Learn more about API rate limit headers.
`X-VaultAPI-VaultId`	The ID of the Vault where this request was initiated.
`X-VaultAPI-UserId`	The ID of the authenticated user who made the request. Returned for all requests which include a `SESSION_ID`.
`X-VaultAPI-TruncatedSessionId`	A shortened version of the `SESSION_ID`. Returned for all requests which include a `SESSION_ID`. This value can identify a group of API requests, but cannot be used to make new API requests.
`X-VaultAPI-Status`	API v23.2+: The `responseStatus` of the API request.

Additional headers returned by Vault API vary by request. For example, Vault Java SDK performance metrics are only returned when the request invokes custom Vault Java SDK code.

The following headers may be returned by Vault API calls:

Response Header Name	Description
`X-VaultAPI-DowntimeExpectedDurationMinutes`	Returned during scheduled Vault upgrades. Indicates the expected duration of downtime in minutes. Learn more about Vault Releases in Vault Help.
`X-VaultAPI-ResponseDelay`	The length of delay, in milliseconds, for a throttled response. Returned for requests which have exceeded the burst limit. Learn more about API rate limit headers.
`X-VaultAPI-SdkCount`	A Vault Java SDK performance metric. Returned for requests which invoke custom Vaut Java SDK code.
`X-VaultAPI-SdkCpuTime`	A Vault Java SDK performance metric. Returned for requests which invoke custom Vaut Java SDK code. Values returned in nanoseconds.
`X-VaultAPI-SdkElapsedTime`	A Vault Java SDK performance metric. Returned for requests which invoke custom Vaut Java SDK code. Values returned in milliseconds.
`X-VaultAPI-SdkGrossMemory`	A Vault Java SDK performance metric. Returned for requests which invoke custom Vaut Java SDK code. Values returned in bytes.
`X-VaultAPI-Connection`	If the request has an associated Connection record, this header returns the `api_name__sys` for the associated connection.
`X-VaultAPI-ReferenceId`	The reference ID for the request, which is specified in the `X-VaultAPI-ReferenceId` request header. If included, this value appears in the `reference_id` column of the API Usage Log.
`X-VaultAPI-DailyLimit`	Deprecated. May appear in v20.3 and below.
`X-VaultAPI-DailyLimitRemaining`	Deprecated. May appear in v20.3 and below.

Vault Java SDK Performance Metrics

In v22.1+, Vault API includes metrics in the response header which allow developers to inspect Vault Java SDK performance during API execution. These response headers are returned with any Vault API request which invokes custom Vault Java SDK code. If the request does not invoke custom code, the response will not include these headers.

These Vault Java SDK performance metrics are also included in the API Usage Log, which is available for download with Vault API or in the Vault UI.

Response Header Name	Description
`X-VaultAPI-SdkCount`	The total number of SDK entry points executed in this request.
`X-VaultAPI-SdkCpuTime`	The total CPU processing time required for this request, in nanoseconds.
`X-VaultAPI-SdkElapsedTime`	The total elapsed time for this request, in milliseconds.
`X-VaultAPI-SdkGrossMemory`	The total gross memory required for this request, in bytes.