HTTP Monitors

HTTP monitors check web endpoints by making HTTP requests and evaluating the response against your assertions. They’re the most feature-rich monitor type, supporting custom headers, request bodies, TLS verification, authentication, and 11 assertion types.

Define this in code. Manage HTTP monitors in your monitoring-as-code workflow: YAML format · Terraform · CI/CD patterns

When to use HTTP monitors

Health check endpoints — verify /health or /status returns 200
API availability — check that key API endpoints respond within latency budgets
Website uptime — confirm marketing pages, app frontends, and landing pages load
SSL certificate expiry — get alerts before certificates expire using the ssl_expiry assertion
Content validation — verify response bodies contain expected data using body_contains, json_path, or regex
Redirect chains — track redirect behavior with redirect_count and redirect_target assertions

How it works

DevHelm sends an HTTP request from each configured probe region at the set frequency
The response is evaluated against all configured assertions
Each assertion records pass/fail with the configured severity (fail or warn)
If any fail-severity assertion fails, the check is marked as failed
Failed checks flow into the incident policy engine

Supported methods

Method	Typical use
`GET`	Health checks, page monitoring, API reads
`POST`	API endpoint testing with request bodies
`PUT`	API update endpoint testing
`PATCH`	Partial update endpoint testing
`DELETE`	Deletion endpoint testing
`HEAD`	Lightweight availability checks (no response body)

Quick example

devhelm monitors create \
  --name "API Health" \
  --type HTTP \
  --url https://api.example.com/health \
  --method GET \
  --frequency 60 \
  --regions us-east,eu-west

monitors:
  - name: API Health
    type: HTTP
    config:
      url: https://api.example.com/health
      method: GET
    frequencySeconds: 60
    regions: [us-east, eu-west]
    assertions:
      - config:
          type: status_code
          expected: "200"
          operator: equals
        severity: fail
      - config:
          type: response_time
          thresholdMs: 2000
        severity: fail

const monitor = await client.monitors.create({
  name: "API Health",
  type: "HTTP",
  config: {
    url: "https://api.example.com/health",
    method: "GET",
  },
  frequencySeconds: 60,
  regions: ["us-east", "eu-west"],
});

monitor = client.monitors.create({
    "name": "API Health",
    "type": "HTTP",
    "config": {
        "url": "https://api.example.com/health",
        "method": "GET",
    },
    "frequencySeconds": 60,
    "regions": ["us-east", "eu-west"],
})

Next steps

Configuration

Every HTTP monitor field — URL, method, headers, body, TLS, auth.

Assertions

All 11 HTTP assertion types with examples.

First HTTP monitor

Step-by-step tutorial.

SSL monitoring

Monitor certificate expiration dates.

Getting Started

Monitoring as Code

Monitoring

Incidents

Alerting

Status Data

Platform

Common Patterns

When to use HTTP monitors

How it works

Supported methods

Quick example

Next steps

Configuration

Assertions

First HTTP monitor

SSL monitoring

​When to use HTTP monitors

​How it works

​Supported methods

​Quick example

​Next steps

Configuration

Assertions

First HTTP monitor

SSL monitoring

When to use HTTP monitors

How it works

Supported methods

Quick example

Next steps