prometheus-erl/prometheus.ex

---

prometheus-erl/prometheus.ex.json

{
  "createdAt": "2016-05-16T22:12:44Z",
  "defaultBranch": "master",
  "description": "Prometheus.io Elixir client",
  "fullName": "prometheus-erl/prometheus.ex",
  "homepage": "",
  "language": "Elixir",
  "name": "prometheus.ex",
  "pushedAt": "2025-08-06T15:39:07Z",
  "stargazersCount": 419,
  "topics": [
    "elixir",
    "instrumentation",
    "metrics",
    "monitoring",
    "prometheus"
  ],
  "updatedAt": "2025-10-26T17:47:58Z",
  "url": "https://github.com/prometheus-erl/prometheus.ex"
}

Prometheus.ex

Elixir Prometheus.io client based on Prometheus.erl.

Dashboard from Monitoring Elixir apps in 2016: Prometheus and Grafana by @skosch.

Example

defmodule ExampleInstrumenter do
  use Prometheus.Metric

  def setup do
    Histogram.new([name: :http_request_duration_milliseconds,
                   labels: [:method],
                   buckets: [100, 300, 500, 750, 1000],
                   help: "Http Request execution time"])
  end

  def instrument(%{time: time, method: method}) do
    Histogram.observe([name: :http_request_duration_milliseconds, labels: [method]], time)
  end
end

or

defmodule ExampleInstrumenter do
  use Prometheus.Metric

  @histogram [name: :http_request_duration_milliseconds,
              labels: [:method],
              buckets: [100, 300, 500, 750, 1000],
              help: "Http Request execution time"]

  def instrument(%{time: time, method: method}) do
    Histogram.observe([name: :http_request_duration_milliseconds, labels: [method]], time)
  end
end

Here histogram will be declared in auto-generated @on_load callback, i.e. you don’t have to call setup manually.

Please read how to measure durations correctly with prometheus.ex.

Integrations / Collectors / Instrumenters

• Ecto collector
• Elli middleware
• Extatus - App to report metrics to Prometheus from Elixir GenServers
• Plugs Instrumenter/Exporter
• Fuse plugin
• OS process info Collector (Linux-only)
• Phoenix instrumenter
• RabbitMQ Exporter

Dashboards

• Beam Dashboards.

Installation

Available in Hex, the package can be installed as:

1. Add prometheus_ex to your list of dependencies in mix.exs:

   def deps do
     [{:prometheus_ex, "~> 4.0"}]
   end

2. Ensure prometheus_ex is started before your application:

   def application do
     [applications: [:prometheus_ex]]
   end