Why it matters
Modern products expose most customer value through APIs. A homepage can stay up while checkout, auth, or billing APIs fail. API monitoring watches those contracts directly.
How it works
You choose a method, URL, headers, and assertions. Each interval the checker performs the request and evaluates rules such as status 2xx, response time under 800ms, and a JSON path returning an expected value.
Authenticated endpoints may require carefully stored headers. Rotate secrets the same way you rotate other production credentials.
Practical example
A checkout team monitors POST https://api.example.com/v1/checkout/quote in a safe sandbox path that creates no charges. Assertions require status 200 and JSON path $.currency equal to USD. When the path starts returning 500, verification opens an incident before shoppers abandon carts.
Common misconception
Hitting any URL is enough
A generic homepage check will not catch a broken /v1/payments route. Monitor the endpoints that represent revenue and login, not only the marketing site.
How Fajita handles this
Fajita API monitors support HTTP methods, status assertions, response-time thresholds, keyword and JSON assertions, and request headers. Start with API monitoring.
Frequently asked questions
Can API monitoring replace integration tests?
No. Monitoring watches live behavior over time. Integration tests verify code before release. Use both.
Should monitors call production write endpoints?
Prefer safe read or sandbox paths. Avoid creating real charges, emails, or irreversible side effects from a monitor.