# Check rendered page content (Content check monitor)

The **Content check** monitor (API type `cntCheck`, shown in the app as **Web content check**) opens your page in
a real Chromium browser, waits until the network is idle, and searches the **rendered** text for your keywords.
It sees text that JavaScript adds after load, which a [Website monitor's](/monitors/types/http/) keyword check
cannot. Use it for single-page apps, client-rendered prices or stock levels, and any page whose important text
is not in the raw HTML.

## At a glance

| | |
|---|---|
| API type token | `cntCheck` |
| Runs from | HostTracker's browser checkpoint fleet - you pick the locations |
| Intervals in the app | 10, 15, 30, 45 minutes, 1, 2, 4, 6, 12, 24 hours, or a cron schedule |
| Default interval | 10 minutes in the app; 3 minutes if omitted in the API |
| Plan gates | the Content check type (`contentCheck`) and keyword monitoring are package features |

## How Down is decided

1. The browser must open the page and reach network idle within the **Timeout**. A navigation error or timeout
   fails the check.
2. After a short settle pause, the visible text (or all text, if **Check only visible content** is off) is
   collected and matched against the keywords.
3. The **Successful check condition** decides the verdict (see the table below).

The page's HTTP status is recorded but does not decide the verdict - an error page that happens to contain your
keyword passes. A failed check is re-checked from other locations before the monitor turns Down.

## Settings reference

The name, interval, cron, tags, **Full Log**, **Open Stats**, subscriptions and locations work as described in
[Common monitor fields](/monitors/types/http/#common-monitor-fields).

| Setting (app label) | API field | Type / allowed values | Default | Plan limits | What it does for you |
|---|---|---|---|---|---|
| **Url/Domain/IP** | `url` | URL or domain | required | - | The page to open. |
| **Timeout** (Main Settings) | `settings.timeout` | milliseconds, 50-120000 (app 1-120 s) | 40000 | - | How long the page may take to load before the check fails. |
| **Content check keywords** | `settings.keyword` | 1-255 characters; several keywords separated by `;` in the API (the app takes them as separate entries) | required | keyword monitoring feature | The text to find in the rendered page. |
| **Successful check condition** | `settings.keywordPresent` + `settings.keywordAny` | booleans | `true` + `false` | - | Present or absent, and how several keywords combine - see below. |
| **Case sensitive match** | `settings.caseSensitive` | boolean | `false` | - | Match exact letter case. |
| **Check only visible content** | `settings.onlyVisible` | boolean | `true` | - | Ignore text hidden by CSS (`display:none`, `visibility:hidden`, zero size). |
| **If selected locations are unavailable** | `locations.fallback` | `starve`, `geo`, `world` | `starve` | - | What happens when your chosen checkpoints are busy. |

What the two condition fields actually do:

| `keywordPresent` | `keywordAny` | The check fails when |
|---|---|---|
| `true` | `false` (API default) | none of the keywords is found - one match is enough |
| `true` | `true` | any keyword is missing - all must be found |
| `false` | `true` | any keyword is found - all must be absent |
| `false` | `false` | every keyword is found at the same time |

:::caution[Several keywords in the app]
The app's four options store these fields as follows: **ANY keyword must be PRESENT on checked page** =
`true`/`true`, **ALL keywords must be PRESENT on checked page** = `true`/`false`, **ANY keywords must be ABSENT
on checked page** = `false`/`true`, **ALL keywords must be ABSENT on checked page** = `false`/`false`. With a
single keyword every option behaves as its label says. With several keywords, read the result from the table
above - the "any" and "all" wording is swapped relative to what the check does.
:::

The editor also shows a **Recheck strategy** selector, but this type has no recheck setting in the API; a
content check always uses the default confirmation (majority vote).

## Set it up in the app

1. On the **Sites** dashboard, click **Add Monitor** and choose **Web content check** in **Monitoring Type**.
2. Enter the page in **Url/Domain/IP** and a name.
3. In **Main Settings**, choose the interval and **Timeout**.
4. In **Response Validation**, enter the **Content check keywords**, choose the **Successful check condition**,
   and set **Case sensitive match** and **Check only visible content**.
5. Pick browser locations in **Monitoring Locations** and click **Save**.

![The Content check editor: content-check keywords, the successful-check condition, and case/visible toggles.](../../../../assets/screenshots/monitor-content-check.png)

## Do it with the API or MCP

```bash
curl -X POST https://api2.host-tracker.com/monitor \
  -H "Authorization: Bearer $HT_TOKEN" -H "Content-Type: application/json" \
  -d '{
    "type": "cntCheck",
    "url": "https://app.example.com/pricing",
    "interval": 600,
    "locations": { "pools": ["allworld"] },
    "settings": { "keyword": "Add to cart", "keywordPresent": true }
  }'
```

Update - fail if an error message appears instead:

```bash
curl -X PATCH https://api2.host-tracker.com/monitor/<monitor-id> \
  -H "Authorization: Bearer $HT_TOKEN" -H "Content-Type: application/json" \
  -d '{ "settings": { "keyword": "Something went wrong;Error 500", "keywordPresent": false, "keywordAny": true } }'
```

MCP (`interval` is passed to the API as-is, in seconds):

```text
create_monitor(type="cntCheck", url="https://app.example.com/pricing", interval=600, pools="allworld",
               settingsJson="{\"keyword\":\"Add to cart\"}")
```

## Recipes

- **A client-rendered element shows up** - `keyword: "In stock"`, defaults for the rest.
- **Every one of several texts must be there** - `keyword: "Login;Pricing"`, `keywordPresent: true`,
  `keywordAny: true`.
- **No error banner** - `keyword: "Error;Something went wrong"`, `keywordPresent: false`, `keywordAny: true`.
- **Hidden text counts too** - `onlyVisible: false`.
- **Plain HTML page** - use the [Website monitor's](/monitors/types/http/) keywords instead; it is lighter and can
  run every minute.

## What happens next

Each check records the load time, the HTTP status and how many elements matched each keyword. A failed match
is re-checked from other locations, then opens an incident and alerts the subscribed contacts.

## Limits and gotchas

- `403 package_limit` - your package does not include Content check or keyword monitoring.
- `422 invalid_settings` - `keyword` is missing or longer than 255 characters, or the timeout is out of range.
- `locations.pools` is required on create.
- Commas do not separate keywords in the API - `"a, b"` is one keyword. Use `;`.

## Related

- [Website / HTTPS monitor](/monitors/types/http/)
- [Page speed monitor](/monitors/types/page-speed/)
- [Transaction monitor](/monitors/types/transaction/)
- [Choosing a monitor type](/monitors/types/choosing/)