Simulating Responses for Testing & Prototyping

Why Simulate Responses?

Simulated responses let you test how an application behaves under different conditions - like errors, empty data, or slow responses - without needing the real server to actually produce them.

Saving Multiple Examples

A single request can have several saved examples - such as a success case, a 404 case, and a validation error case - each returned by the mock server depending on how the request is matched.

Common Scenarios to Simulate

ScenarioWhy It's Useful
Error responses (4xx/5xx)Test how the app handles failures
Empty or null dataTest edge-case UI states
Large datasetsTest pagination or performance handling

Prototyping New Features

Simulated responses also let teams prototype and demo a feature that depends on an API endpoint that hasn't been built yet.

Simulating responses is closely tied to how an API is planned in the first place - let's zoom out and look at API design and development.

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