> ## Documentation Index
> Fetch the complete documentation index at: https://docs.larm.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Monitors

> Monitor types and configuration options

Larm supports five monitor types. Each type has its own configuration, but they all share common settings for check intervals, timeouts, and disruption confirmation.

## Common settings

These settings apply to all monitor types.

| Setting            | Default | Description                                                                              |
| ------------------ | ------- | ---------------------------------------------------------------------------------------- |
| **Check interval** | 3 min   | How often to run the check (minimum varies by plan: 3 min Free, 1 min Pro, 30s Business) |
| **Timeout**        | 10s     | How long to wait for a response (1s–60s)                                                 |
| **Confirm down**   | 1 min   | Minutes the monitor must stay failing before being marked down                           |
| **Confirm up**     | 3 min   | Minutes the monitor must stay passing before being marked recovered                      |

Confirmation windows help smooth out brief interruptions. Set **Confirm down** to a few minutes if you want to avoid alerts for momentary blips.

## HTTP

Checks a URL and validates the response status code, headers, and body content.

| Field                     | Description                                                           |
| ------------------------- | --------------------------------------------------------------------- |
| **URL**                   | The URL to check (http or https)                                      |
| **Method**                | HTTP method (GET, POST, HEAD, etc.)                                   |
| **Expected status codes** | Status codes that count as healthy (e.g. 200, 301)                    |
| **Follow redirects**      | Whether to follow HTTP redirects                                      |
| **Headers**               | Custom request headers (up to 20, each value up to 8KB)               |
| **Body**                  | Request body for POST/PUT/PATCH (up to 64KB)                          |
| **Expected keyword**      | A string that must appear in the response body (up to 1000 bytes)     |
| **Unexpected keyword**    | A string that must not appear in the response body (up to 1000 bytes) |

Larm checks your URL from multiple global locations simultaneously and uses majority voting to confirm the result — a single probe failure won't trigger a false alert.

## TCP

Checks that a host is accepting TCP connections on a given port.

| Field    | Description            |
| -------- | ---------------------- |
| **Host** | Hostname or IP address |
| **Port** | TCP port number        |

Use this for databases, mail servers, game servers, or any service that listens on a TCP port.

## DNS

Checks that a DNS record resolves to the expected values.

| Field                | Description                                     |
| -------------------- | ----------------------------------------------- |
| **Host**             | The domain to query                             |
| **Record type**      | DNS record type (A, AAAA, CNAME, MX, TXT, etc.) |
| **Nameserver**       | IP address of the nameserver to query           |
| **Expected records** | Values the DNS response should contain          |

Use this to verify DNS propagation, detect hijacking, or monitor record changes.

## Heartbeat

Expects a periodic HTTP ping. If the ping stops arriving, the monitor goes down.

| Field                  | Description                                                   |
| ---------------------- | ------------------------------------------------------------- |
| **Expected interval**  | How often the ping should arrive (10s to 24h, plan-dependent) |
| **Consecutive misses** | Number of missed intervals before alerting (default 2)        |

When you create a heartbeat monitor, you get a unique token and URL. Ping it from your cron jobs, scheduled tasks, or background workers:

```bash theme={null}
curl https://app.larm.dev/api/heartbeat/YOUR_TOKEN
```

See the [heartbeat API reference](/api-reference/heartbeat) for details.

## Synthetic

<Note>Synthetic monitoring is available on Pro and Business plans.</Note>

Runs a Playwright browser script against your application. Use this for testing login flows, checkout processes, or any user journey that can't be verified with a simple HTTP request.

| Field                  | Description                                                          |
| ---------------------- | -------------------------------------------------------------------- |
| **Script**             | Playwright script to execute (up to 64KB)                            |
| **Interval**           | How often to run the check (minimum 5 min on Pro, 3 min on Business) |
| **Confirm down after** | Consecutive failures before marking as down (default 3)              |
| **Confirm up after**   | Consecutive passes before marking as recovered (default 1)           |

Synthetic monitors use count-based confirmation instead of time-based. A `confirm_down_after` of 3 means three consecutive failing checks before we alert you. This prevents flaky scripts or transient runner issues from triggering false alerts.