--- title: "Backend Listener" description: "Configure the JMeter Backend Listener listeners: properties, defaults, and practical usage notes for building reliable load tests." url: https://docs.jmeter.ai/components/backend-listener/ lastUpdated: 2026-10-01 source: docs.jmeter.ai --- # Backend Listener *Part of the **Listeners** category. Also documented in context in the [full Component Reference](/user-manual/component-reference/#backend-listener).* **TL;DR:** the Backend Listener streams live sample results to an external time-series backend (InfluxDB, Graphite, Elasticsearch, Prometheus via a bridge) during the run, so you can watch a real-time dashboard instead of waiting for the test to finish and parsing a `.jtl` file. ![Backend Listener](/images/screenshots/backend_listener.png) The backend listener is an Asynchronous listener that enables you to plug custom implementations of [BackendListenerClient](https://jmeter.apache.org/api/org/apache/jmeter/visualizers/backend/BackendListenerClient.html). By default, a Graphite implementation is provided. | Name | Required | Description | | --- | --- | --- | | Name | Yes | Descriptive name for this element that is shown in the tree. | | Backend Listener implementation | Yes | Class of the `BackendListenerClient` implementation. | | Async Queue size | Yes | Size of the queue that holds the SampleResults while they are processed asynchronously. | | Parameters | Yes | Parameters of the `BackendListenerClient` implementation. | The following parameters apply to the [GraphiteBackendListenerClient](https://jmeter.apache.org/api/org/apache/jmeter/visualizers/backend/graphite/GraphiteBackendListenerClient.html) implementation: | Name | Required | Description | | --- | --- | --- | | graphiteMetricsSender | Yes | `org.apache.jmeter.visualizers.backend.graphite.TextGraphiteMetricsSender` or `org.apache.jmeter.visualizers.backend.graphite.PickleGraphiteMetricsSender` | | graphiteHost | Yes | Graphite or InfluxDB (with Graphite plugin enabled) server host | | graphitePort | Yes | Graphite or InfluxDB (with Graphite plugin enabled) server port, defaults to `2003`. Note `PickleGraphiteMetricsSender` (port `2004`) can only talk to Graphite server. | | rootMetricsPrefix | Yes | Prefix of metrics sent to backend. Defaults to “`jmeter`.” Note that JMeter does not add a separator between the root prefix and the samplerName which is why the trailing dot is currently needed. | | summaryOnly | Yes | Only send a summary with no detail. Defaults to `true`. | | samplersList | Yes | Defines the names (labels) of sample results to be sent to the back end. If `useRegexpForSamplersList=false` this is a list of semi-colon separated names. If `useRegexpForSamplersList=true` this is a regular expression which will be matched against the names. | | useRegexpForSamplersList | Yes | Consider samplersList as a regular expression to select the samplers for which you want to report metrics to backend. Defaults to `false`. | | percentiles | Yes | The percentiles you want to send to the backend. A percentile may contain a fractional part, for example `12.5`. (The separator is always ”.”) List must be semicolon separated. Generally 3 or 4 values should be sufficient. | See also [Real-time results](/user-manual/realtime-results/) for more details. ![Grafana dashboard](/images/screenshots/grafana_dashboard.png) *Grafana dashboard* Since JMeter 3.2, an implementation that allows writing directly in InfluxDB with a custom schema. It is called `InfluxdbBackendListenerClient`. The following parameters apply to the [InfluxdbBackendListenerClient](https://jmeter.apache.org/api/org/apache/jmeter/visualizers/backend/influxdb/InfluxdbBackendListenerClient.html) implementation: | Name | Required | Description | | --- | --- | --- | | influxdbMetricsSender | Yes | `org.apache.jmeter.visualizers.backend.influxdb.HttpMetricsSender` | | influxdbUrl | Yes | Influx URL (example: `http://influxHost:8086/write?db=jmeter`) | | influxdbToken | No | InfluxDB 2 [authentication token](https://v2.docs.influxdata.com/v2.0/security/) (example: `HE9yIdAPzWJDspH_tCc2UvdKZpX==`); since 5.2. | | application | Yes | Name of tested application. This value is stored in the ‘`events`’ measurement as a tag named ‘`application`’ | | measurement | Yes | Measurement as per [Influx Line Protocol Reference](https://docs.influxdata.com/influxdb/v1.1/write_protocols/line_protocol_reference/). Defaults to “`jmeter`”. | | summaryOnly | Yes | Only send a summary with no detail. Defaults to `true`. | | samplersRegex | Yes | Regular expression which will be matched against the names of samples and sent to the back end. | | testTitle | Yes | Test name. Defaults to `Test name`. This value is stored in the ‘`events`’ measurement as a field named ‘`text`’. JMeter generate automatically at the start and the end of the test an annotation with this value ending with ’ started’ and ’ ended’ | | eventTags | No | Grafana allow to display tag for each annotation. You can fill them here. This value is stored in the ‘`events`’ measurement as a tag named ‘`tags`’. | | percentiles | Yes | The percentiles you want to send to the backend. A percentile may contain a fractional part, for example `12.5` (The separator is always “`.`”). List must be semicolon separated. Generally three or four values should be sufficient. | | TAG_WhatEverYouWant | No | You can add as many custom tags as you want. For each of them, create a new line and prefix its name by “`TAG_`” | See also [Real-time results](/user-manual/realtime-results/) and [Influxdb annotations in Grafana](http://docs.grafana.org/reference/annotations/#influxdb-annotations) for more details. There is also a [subsection on configuring the listener for InfluxDB v2](/user-manual/realtime-results/#influxdb_v2). Since JMeter 5.4, an implementation that writes all sample results to InfluxDB. It is called `InfluxDBRawBackendListenerClient`. It is worth noting that this will use more resources than the `InfluxdbBackendListenerClient`, both by JMeter and InfluxDB due to the increase in data and individual writes. The following parameters apply to the [InfluxDBRawBackendListenerClient](/../api/org/apache/jmeter/visualizers/backend/influxdb/InfluxDBRawBackendListenerClient/) implementation: | Name | Required | Description | | --- | --- | --- | | influxdbMetricsSender | Yes | `org.apache.jmeter.visualizers.backend.influxdb.HttpMetricsSender` | | influxdbUrl | Yes | Influx URL (e.g. [http://influxHost:8086/write?db=jmeter](http://influxHost:8086/write?db=jmeter) or, for the cloud, [https://eu-central-1-1.aws.cloud2.influxdata.com/api/v2/write?org=org-id&bucket=jmeter](https://eu-central-1-1.aws.cloud2.influxdata.com/api/v2/write?org=org-id&bucket=jmeter)) | | influxdbToken | No | InfluxDB 2 [authentication token](https://v2.docs.influxdata.com/v2.0/security/) (e.g. HE9yIdAPzWJDspH_tCc2UvdKZpX==) | | measurement | Yes | Measurement as per [Influx Line Protocol Reference](https://docs.influxdata.com/influxdb/v1.7/write_protocols/line_protocol_reference/). Defaults to “`jmeter`.” | ^ ### Common gotchas - It runs **asynchronously in a queue** — under very high throughput, an undersized queue can drop metrics rather than block the test; increase `async.queue.size` if you see gaps in the dashboard that don’t match the actual run. - This is the right tool for **live observability**; it doesn’t replace the standard `.jtl` results file or the HTML Dashboard Report for post-run analysis and archiving. - Configuration (URL, database/bucket, application name tag) is backend-specific — see [Grafana / InfluxDB / Backend Listener](/topics/grafana-influx-backend-listener/) for a working setup. - Adds CPU/network overhead on the injector itself; on already-saturated load generators, consider a lighter listener or sampling instead. ## Related - [Grafana / InfluxDB / Backend Listener](/topics/grafana-influx-backend-listener/) - [Coordinated Omission Calculator](/tools/coordinated-omission/) - [Full Component Reference](/user-manual/component-reference/) - [Functions and Variables](/user-manual/functions/)