Feature

Response Validation

Go beyond uptime. Validate that your APIs return exactly what you expect.

200 OK isn't always OK

Traditional uptime monitors only check if your API responds. But a 200 status code doesn't guarantee your API is working correctly. The response could be empty, malformed, or contain stale data.

APIAssert validates the actual content of your responses, catching issues that status codes miss.

  • JSON path assertions ($.data.users[0].id)
  • Status code validation
  • Response time thresholds
  • Header verification
  • Regex pattern matching
assertions.json
// Define what "healthy" looks like
"assertions": [
{ "status" : 200 },
{ "responseTime" : { "lt": 500 }},
{ "$.user.active" : true },
{ "$.data" : "exists" }
]

Common use cases

Response validation helps you catch issues across your entire API surface.

API Contract Testing

Ensure your API returns the expected schema. Catch breaking changes before they reach production.

E-commerce Checkout

Verify that product prices, inventory counts, and payment processing return correct values.

Authentication Flows

Confirm that login endpoints return valid tokens and user data in the expected format.

Third-Party Integrations

Monitor external APIs you depend on. Get alerted when their responses change unexpectedly.

Data Pipeline Health

Validate that your data APIs return fresh data, not stale cache or empty results.

SLA Compliance

Prove to customers that your API meets response time and reliability commitments.

Powerful assertion types

{ }

JSON Path

Use JSONPath expressions to validate any value in your response body.

$.data.users[0].email == "[email protected]"
ms

Response Time

Set thresholds for acceptable response times. Get alerted when APIs slow down.

responseTime < 500ms
.*

Regex Patterns

Match values against regular expressions for flexible validation.

$.user.email matches /^[\w-]+@[\w-]+\.\w+$/