Response Validation

Response validation lets you verify the content of HTTP responses, not just the status code.

Validation Types

JSONPath Expressions

Extract values from JSON responses using JSONPath expressions and compare them against expected values.

Example: Verify that a health endpoint returns "ok":

• JSONPath: $.status
• Expected value: ok

For an API response like:

{
  "status": "ok",
  "version": "2.1.0"
}

The JSONPath $.status extracts "ok", which matches the expected value.

Common JSONPath Expressions

Text Containment

Verify that the response body contains a specific text string. This is useful for:

• HTML pages that should contain specific content
• API responses where you want to verify a keyword exists
• Simple health checks that return plain text

How Validation Works

1. The check runs normally and receives a response
2. If the status code matches the expected code, response validation runs
3. If validation fails, the check is marked as failed (same as a status code mismatch)
4. Smart verification and consecutive failure thresholds apply to validation failures

Limitations

• Response validation is only available for website and API checks (not TCP/UDP)
• JSONPath validation requires the response to be valid JSON
• Text containment is case-sensitive
• The full response body is available for validation (no size limit on the validation itself)

Best Practices

• Use JSONPath validation for structured API responses
• Use text containment for HTML pages or simple text responses
• Keep validation expressions simple and focused on critical values
• Test your JSONPath expressions against sample responses before configuring checks