This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Boot 3.4.5!

Metrics (metrics)

The metrics endpoint provides access to application metrics to diagnose the metrics the application has recorded. This endpoint should not be "scraped" or used as a metrics backend in production. Its purpose is to show the currently registered metrics so users can see what metrics are available, what their current values are, and if triggering certain operations cause any change in certain values. If you want to diagnose your applications through the metrics they collect, you should use an external metrics backend. In this case, the metrics endpoint can still be useful.

Retrieving Metric Names

To retrieve the names of the available metrics, make a GET request to /actuator/metrics, as shown in the following curl-based example:

$ curl 'http://localhost:8080/actuator/metrics' -i -X GET

The resulting response is similar to the following:

HTTP/1.1 200 OK
Content-Type: application/vnd.spring-boot.actuator.v3+json
Content-Length: 154

{
  "names" : [ "jvm.buffer.count", "jvm.buffer.memory.used", "jvm.buffer.total.capacity", "jvm.memory.committed", "jvm.memory.max", "jvm.memory.used" ]
}

Response Structure

The response contains details of the metric names. The following table describes the structure of the response:

Path Type Description

names

Array

Names of the known metrics.

Retrieving a Metric

To retrieve a metric, make a GET request to /actuator/metrics/{metric.name}, as shown in the following curl-based example:

$ curl 'http://localhost:8080/actuator/metrics/jvm.memory.max' -i -X GET

The preceding example retrieves information about the metric named jvm.memory.max. The resulting response is similar to the following:

HTTP/1.1 200 OK
Content-Disposition: inline;filename=f.txt
Content-Type: application/vnd.spring-boot.actuator.v3+json
Content-Length: 555

{
  "name" : "jvm.memory.max",
  "description" : "The maximum amount of memory in bytes that can be used for memory management",
  "baseUnit" : "bytes",
  "measurements" : [ {
    "statistic" : "VALUE",
    "value" : 2.399141885E9
  } ],
  "availableTags" : [ {
    "tag" : "area",
    "values" : [ "heap", "nonheap" ]
  }, {
    "tag" : "id",
    "values" : [ "CodeHeap 'profiled nmethods'", "G1 Old Gen", "CodeHeap 'non-profiled nmethods'", "G1 Survivor Space", "Compressed Class Space", "Metaspace", "G1 Eden Space", "CodeHeap 'non-nmethods'" ]
  } ]
}

Query Parameters

The endpoint uses query parameters to drill down into a metric by using its tags. The following table shows the single supported query parameter:

Parameter Description

tag

A tag to use for drill-down in the form name:value.

Response Structure

The response contains details of the metric. The following table describes the structure of the response:

Path Type Description

name

String

Name of the metric

description

String

Description of the metric

baseUnit

String

Base unit of the metric

measurements

Array

Measurements of the metric

measurements[].statistic

String

Statistic of the measurement. (TOTAL, TOTAL_TIME, COUNT, MAX, VALUE, UNKNOWN, ACTIVE_TASKS, DURATION).

measurements[].value

Number

Value of the measurement.

availableTags

Array

Tags that are available for drill-down.

availableTags[].tag

String

Name of the tag.

availableTags[].values

Array

Possible values of the tag.

Drilling Down

To drill down into a metric, make a GET request to /actuator/metrics/{metric.name} using the tag query parameter, as shown in the following curl-based example:

$ curl 'http://localhost:8080/actuator/metrics/jvm.memory.max?tag=area%3Anonheap&tag=id%3ACompressed+Class+Space' -i -X GET

The preceding example retrieves the jvm.memory.max metric, where the area tag has a value of nonheap and the id attribute has a value of Compressed Class Space. The resulting response is similar to the following:

HTTP/1.1 200 OK
Content-Disposition: inline;filename=f.txt
Content-Type: application/vnd.spring-boot.actuator.v3+json
Content-Length: 263

{
  "name" : "jvm.memory.max",
  "description" : "The maximum amount of memory in bytes that can be used for memory management",
  "baseUnit" : "bytes",
  "measurements" : [ {
    "statistic" : "VALUE",
    "value" : 1.073741824E9
  } ],
  "availableTags" : [ ]
}