---
title: "Connect Prometheus Alertmanager"
description: "Send Prometheus alerts to Firefight through an Alertmanager webhook receiver."
canonical: https://firefight.app/docs/alerts/alertmanager
---

# Connect Prometheus Alertmanager

Firefight has a dedicated alert source for Prometheus Alertmanager. Alertmanager sends a group of alerts in each request, and Firefight turns each one into its own alert that resolves when Prometheus resolves it.

## Set up the Firefight side

Go to **Settings → Alert Sources**, click **Add source**, give it a name like "Prometheus production", and pick the **Prometheus Alertmanager** provider. When you create it, Firefight opens the source's setup. It shows the ingest URL and a **Copy token** button for the source's secret token, and the same steps as this page.

## Set up the Prometheus Alertmanager side

1. In `alertmanager.yml`, add a receiver with a `webhook_configs` entry whose `url` is the ingest URL. Leave `send_resolved` on.
2. Under that entry's `http_config`, add `authorization` with `credentials` set to the token. Alertmanager sends it as `Authorization: Bearer`.
3. Route the alerts that should reach Firefight to the receiver, then reload Alertmanager.

Requests that fail the check are rejected with `401`, and the source's row in **Settings → Alert Sources** shows the rejection.

```yaml
receivers:
  - name: firefight
    webhook_configs:
      - url: https://<your Firefight host>/api/v1/alerts/<endpoint-path>
        send_resolved: true
        http_config:
          authorization:
            credentials: <token>
```

Basic auth works too. Set `basic_auth` with any `username` and the token as the `password`.

## What Firefight reads

Each alert gets these fields, which you can match in your [routing rules](https://firefight.app/docs/alerts/routing-rules.md).

| Field | Value |
|---|---|
| `title` | The `alertname` label |
| `description` | The `summary` and `description` annotations |
| `service` | The `service` label, else `job` |
| `severity_raw` | The `severity` label |
| `team` | The `team` label |
| `environment` | The `environment` label, else `env` |
| `url` | The alert's `generatorURL`, the expression in Prometheus |

The alert's title in Slack and on the dashboard links to its page in Prometheus Alertmanager.

## Firing and resolving

Each alert in the group is its own alert in Firefight, identified by Alertmanager's fingerprint for its labels. A repeat notification counts on the same alert, and a resolved notification resolves it.

See [Grouping & deduplication](https://firefight.app/docs/alerts/grouping-and-deduplication.md) for how repeat firings collapse into one alert.