API Uptime Monitoring: A Guide

Short answer. API документацию monitoring means automated, regular checks that your endpoints are reachable and returning correct responses. Set up a health check that's Ping every minute, watch the status code and response time, and wire alerts to Telegram, Slack, or a webhook. With enterno.io you can run up to 10 HTTP monitors for free with one-minute checks and instant downtime alerts.

Why monitor the API separately from the site

An API fails differently than a website. Your homepage can return 200 OK while the backend endpoint /api/v1/orders is already throwing 500 because a queue crashed or the database connection pool is exhausted. The user sees a blank screen, but your domain-root uptime dashboard is green. That's why API endpoints need to be monitored as separate targets.

Rule of thumb: monitor what matters to the user, not what's convenient to check. If your product is an API, its SLA is measured against key endpoints — not a static landing page.

The health-check endpoint

The first step is a dedicated health check that doesn't just return 200 but actually verifies dependencies (DB, Redis, external services). The simplest check from a terminal:

curl -sS -o /dev/null -w "%{http_code} %{time_total}s\n" https://api.example.com/health

This command prints the HTTP code and total response time — exactly what a monitor should record every minute.

For more on designing these endpoints, see health-check endpoints.

Creating a monitor via the API

enterno.io exposes a REST API (v4) that lets you create monitors programmatically — handy for IaC and CI pipelines. Conceptually:

curl -X POST https://enterno.io/api/v4/monitors \
  -H "X-API-Key: ent_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://api.example.com/health",
    "check_type": "http",
    "interval_minutes": 1,
    "expected_code": 200,
    "notify_telegram": true
  }'

A single POST creates a monitor that checks once a minute and expects 200 — from there the platform pings the endpoint and alerts you on any deviation.

What to check

• HTTP status — the expected code (200, 201 or a custom one for the health endpoint).
• Response time — p50/p95 latency, not just up/down.
• Response body — presence of a key field (e.g. "status":"ok"), not just an empty 200.
• SSL certificate — days to expiry, chain, protocol.
• Dependencies — DB, cache, external APIs the endpoint relies on.

Signal	Why it matters	Alert threshold
HTTP code	Basic availability	not the expected code (e.g. ≠ 200)
Response time	Performance degradation	p95 > 1000 ms
SSL certificate	TLS expiry	< 14 days to expiry
Response body	Data correctness	expected JSON field missing

Intervals and regions

For critical APIs, use a one-minute interval — it minimizes MTTD (mean time to detect). Multi-region checks (RU, EU, US) filter out false positives caused by a single provider's network issues: if the endpoint is unreachable from only one region, that's more likely a routing problem than a service outage.

Alerts

A downtime event is useless if nobody hears about it. enterno.io supports Telegram, Slack, webhook, PagerDuty, and Jira. A webhook lets you plug the alert into your own incident system. To avoid drowning in noise, read alerting best practices.

Don't alert on a single blip. Require 2–3 consecutive failures before opening an incident — that removes short-lived network flaps.

SLA and metrics

From the check history you derive uptime (% of time available) and MTTR (mean time to recovery). Those numbers are the foundation of customer-facing SLA reports. Which metrics matter most for APIs is covered in API performance metrics.

Automation for agents and LLMs

If you work in Claude, Cursor, or Zed, you can manage monitors through the MCP server right from your assistant. Details in the MCP server for monitoring.

FAQ

How is API monitoring different from website monitoring?

API monitoring validates specific endpoints, response codes, and JSON structure, whereas website monitoring usually checks only homepage availability. An API can return 500 while the site's status looks green.

How often should I check an API?

For critical services, once a minute. That's the minimum interval on the free enterno.io plan and the optimal balance between detection speed and load.

Do I need a dedicated health-check endpoint?

Yes. A dedicated /health that verifies dependencies is more reliable than monitoring business endpoints with side effects (like creating an order).

Can I monitor an authenticated API?

It's best to expose a public, unauthenticated health check that reflects system state without leaking data. That way the monitor never needs secrets.

Start monitoring your API

Create your first HTTP monitor for free: go to monitors. Up to 10 targets with one-minute checks, Telegram/Slack alerts, and history for SLA. For the fundamentals of uptime monitoring, see the general uptime guide.