# URL Monitor

- Import the `UrlMonitor` construct from `checkly/constructs`.
- When adding `assertions`, always use `UrlAssertionBuilder`.
- **Important:** The target URL must be publicly accessible — checks run on Checkly's cloud, not locally.
- **Plan-gated properties:** `retryStrategy`, `runParallel`, and higher frequencies are not available on all plans. Check entitlements matching `UPTIME_CHECKS_*` before using these. Omit any property whose entitlement is disabled — Checkly applies safe defaults. See `npx checkly skills manage` for details.

**Reference:** https://www.checklyhq.com/docs/constructs/url-monitor/

```typescript
import { AlertEscalationBuilder, Frequency, RetryStrategyBuilder, UrlAssertionBuilder, UrlMonitor } from 'checkly/constructs'

new UrlMonitor('example-url-monitor', {
  name: 'Example URL Monitor',
  activated: true,
  locations: [
    'eu-central-1',
    'eu-west-2',
  ],
  frequency: Frequency.EVERY_5M,
  alertEscalationPolicy: AlertEscalationBuilder.runBasedEscalation(1, {
    amount: 0,
    interval: 5,
  }, {
    enabled: false,
    percentage: 10,
  }),
  retryStrategy: RetryStrategyBuilder.noRetries(),
  runParallel: true,
  degradedResponseTime: 5000,
  maxResponseTime: 20000,
  request: {
    url: 'INSERT_URL',
    ipFamily: 'IPv4',
    assertions: [
      UrlAssertionBuilder.statusCode().equals(200),
    ],
  },
})
```