Checkly Has a Free API — Here's How to Monitor Your APIs and Web Apps with Code

A DevOps lead told me: 'We had synthetic monitoring in Datadog — $15/check/month. 20 checks = $300/month just to know if our APIs were up.' Checkly does the same thing with Playwright-based checks starting at $0.

What Checkly Offers for Free

Checkly Hobby plan:

• 50,000 check runs/month
• 5 browser checks (Playwright scripts)
• 20 API checks (HTTP endpoint monitoring)
• Checks as Code — write checks in TypeScript, deploy from CI/CD
• Alerting — email, Slack, PagerDuty, Opsgenie
• Private locations — run checks from your own infrastructure
• Dashboards — public status dashboards

Quick Start

npm create checkly
cd my-project
npx checkly test  # Run checks locally
npx checkly deploy  # Deploy to Checkly

API Check (TypeScript)

// __checks__/api/health.check.ts
import { ApiCheck, AssertionBuilder } from 'checkly/constructs';

new ApiCheck('api-health', {
  name: 'API Health Check',
  activated: true,
  frequency: 5, // every 5 minutes
  locations: ['us-east-1', 'eu-west-1'],
  request: {
    method: 'GET',
    url: 'https://api.yourapp.com/health',
    assertions: [
      AssertionBuilder.statusCode().equals(200),
      AssertionBuilder.jsonBody('$.status').equals('healthy'),
      AssertionBuilder.responseTime().lessThan(2000)
    ]
  },
  alertChannels: ['slack-alerts']
});

Browser Check (Playwright)

// __checks__/browser/login-flow.spec.ts
import { test, expect } from '@playwright/test';

test('user can login and see dashboard', async ({ page }) => {
  await page.goto('https://yourapp.com/login');

  await page.fill('[name=email]', '[e-mail]');
  await page.fill('[name=password]', 'testpassword');
  await page.click('button[type=submit]');

  await expect(page).toHaveURL('/dashboard');
  await expect(page.locator('h1')).toContainText('Dashboard');

  // Check that key elements load
  await expect(page.locator('[data-testid=stats]')).toBeVisible();
});

REST API

# List checks
curl 'https://api.checklyhq.com/v1/checks' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'X-Checkly-Account: YOUR_ACCOUNT_ID'

# Get check results
curl 'https://api.checklyhq.com/v1/check-results/CHECK_ID?limit=10' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'X-Checkly-Account: YOUR_ACCOUNT_ID'

# Create an API check
curl -X POST 'https://api.checklyhq.com/v1/checks' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'X-Checkly-Account: YOUR_ACCOUNT_ID' \
  -H 'Content-Type: application/json' \
  -d '{
    "name": "Production API",
    "checkType": "API",
    "activated": true,
    "frequency": 5,
    "locations": ["us-east-1"],
    "request": {
      "method": "GET",
      "url": "https://api.yourapp.com/health"
    },
    "assertions": [
      {"source": "STATUS_CODE", "comparison": "EQUALS", "target": "200"}
    ]
  }'

# Trigger a check manually
curl -X POST 'https://api.checklyhq.com/v1/triggers/CHECK_ID' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'X-Checkly-Account: YOUR_ACCOUNT_ID'

CI/CD Integration

# .github/workflows/checkly.yml
name: Checkly E2E Tests
on: [deployment_status]

jobs:
  test:
    if: github.event.deployment_status.state == 'success'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
      - run: npm ci
      - run: npx checkly test --record
        env:
          CHECKLY_API_KEY: ${{ secrets.CHECKLY_API_KEY }}
          CHECKLY_ACCOUNT_ID: ${{ secrets.CHECKLY_ACCOUNT_ID }}
          ENVIRONMENT_URL: ${{ github.event.deployment_status.target_url }}
      - run: npx checkly deploy --force

Checkly vs Datadog Synthetics

Checkly	Datadog Synthetics
Free: 50K runs/month	$5-12/test/month
Playwright native	Custom syntax
Checks as Code	Web UI config
CLI-first workflow	Dashboard-first
Open source CLI	Proprietary

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Need to monitor your scrapers? Check out my web scraping actors on Apify — with built-in monitoring.

Need API monitoring? Email me at [e-mail].