Definition
Keyword monitoring (content-check monitoring) verifies that a response body contains an expected piece of text — or is missing an unexpected one. It catches failures that a status-code check can't, where the server returns HTTP 200 but the content is wrong.
For example, a page might load successfully but display "Database connection failed" instead of real content. A keyword check looking for an expected phrase (or flagging an error phrase) detects this even though the status code looks healthy.
Why It Matters
Status codes can lie. Misconfigured apps, error pages served with 200, and partial failures all return "success" while showing broken content to users. Keyword monitoring closes that gap by validating what's actually on the page, not just the HTTP header.
How It Works
You specify a keyword or phrase and whether it should be present or absent. The monitor fetches the page and inspects the response body: if an expected keyword is missing (or a forbidden one appears), the check fails — even when the status code is 200. It's a deeper form of correctness checking.
Real-World Example
A store's product page returns HTTP 200 but a backend error replaces the catalog with "Service temporarily unavailable." A keyword check expecting the text "Add to cart" fails because that phrase is gone — catching a broken page a status-only check would have called healthy.
Best Practices
- Choose a keyword that only appears when the page truly works
- Use absence checks to flag known error phrases
- Combine keyword checks with status-code and response-time checks
- Pick stable text unlikely to change with normal content updates
- Apply keyword checks to your most critical pages and flows
Common Mistakes
- Trusting a 200 status and never validating page content
- Choosing a keyword that changes often, causing false failures
- Picking text that appears even on error pages
- Relying on keyword checks alone without status or timing checks
- Applying content checks everywhere instead of on critical pages
In Monitoristic
Monitoristic verifies the expected HTTP status code on each check. If you need content-level verification, the practical pattern is to point the monitor at an endpoint that returns a non-2xx status when the expected content or dependency is missing, so a broken state shows up as a failed check.