API Monitoring

Website uptime monitoring checks whether a URL returns a 200 response. But a 200 response from an API endpoint does not necessarily mean the API is working. An endpoint can return 200 with an empty body, an error message, or malformed JSON — all of which would be invisible to a basic HTTP check while completely breaking the applications that consume the API.

API failures also tend to surface in unexpected ways. An authentication endpoint that starts returning 401 for valid credentials will silently log out users. A search API that returns an empty result set instead of a 500 will make it appear as if no records exist. A payment endpoint that times out after 29 seconds — just inside the timeout window — will cause transaction failures without triggering a connectivity alert.

Proper API monitoring goes beyond connectivity checks. It validates that the response contains the expected data structure, that critical fields are present, that latency stays within acceptable bounds, and that authentication is functioning correctly. Only then can you confidently say an API endpoint is healthy.

These failures carry real cost. A payment API returning empty responses processes zero orders while the status page still shows green. A third-party API outage that takes down checkout becomes a revenue incident attributed to your team, not the vendor whose endpoint actually failed. And if the affected endpoint is covered by a customer-facing SLA, a validation gap that goes undetected for hours can trigger service credits that monitoring would have prevented.

NetTests sends fully configurable HTTP requests to your API endpoints on a schedule you define. Each request can carry custom headers (for authentication tokens, API keys, or content negotiation), a request body (for POST and PUT endpoints), and specific configuration for HTTPS and redirect behavior.

The response is validated against your configured criteria: expected status code, response body contents, response time threshold, and header values. If any validation fails, an alert is dispatched immediately. Every check result — including the full response body, headers, and latency measurement — is stored for later review.

For GraphQL APIs, NetTests can send introspection queries and operation requests using the correct content type and query format, validating that your schema and resolvers are functioning correctly across deployments.

Alerts reach your team through email, Slack, Microsoft Teams, or any webhook-compatible incident tool. The dashboard lists every endpoint you monitor with its current status, last response time, and a sparkline of recent checks — so a slow creep in latency is visible long before it crosses an alert threshold. Time to first alert is typically under a minute: the moment a check fails validation, the notification goes out immediately, with no batching delay. To avoid false alarms from transient network blips, you can require a failure to repeat across a configurable number of consecutive checks before NetTests alerts your team.