Mocking a REST API - with Response Simulation

Creating GET API

In the previous post, we create a mock REST API which responds to HTTP GET requests with a greeting message. In this post, we will further enhance the mock REST API we created previously. We will be adding additional responses to the REST API and switch-on the s imulation capability of the mock API server..

Step 1: Open the /say-hello api in the API editor

Locate the /say-hello API in the navigation tree on the left. Since /say-hello responds to HTTP GET requests, expand the GET node in the navigation tree. Click on /say-hello to select the API and open it in the editor.

Side navigation panel showing list of mock API endpoints in the API editor

Step 2: Add additional responses to the API

After the /say-hello API is loaded into the editor, scroll down to the Alternate HTTP Responses section of the editor. We will make use of the fields in this section to define the additional API responses. For each response that we add to the API, we will need to provide the HTTP Response Code, HTTP Content-Type, and Response Body.

Press the Save/Add Alternate Response button to add the new response to the table.

We have added 10 responses to the /say-hello API

Image showing how additional (alternate) responses can be added to an existing mock API

Step 3: Save the changes made to the API

Scroll to top of the API Editor to save all the changes we have made to the /say-hello API.

Image showing the save button that saves

Step 4: Enable API Response Simulation

We need to enable simulation to make /say-hello return a different response each time it is called by a client application. When simulation is activated, the /say-hello API will pick one of ten responses we added to the Alternate HTTP Responses section.
To activate response simulation, press the Simulation Mode: Off button

Image showing the button with which the user can enable (or disable) response simulation feature of the mock server

Step 5: Copy the API URL

To call this mock API, the complete URL of the API must be known. The complete URL is shown in the Complete API Endpoint URL textbox. And the URL can be copied by clicking on the Copy URL button

Image showing the auto-generated URL of the mocked API endpoint

Begin using the mock REST API with Response Simulation

You can call this mock REST API from your application code or from a command-line program such as cURL.
Please remember that the API will return only one of the ten responses at a time. To view all the responses, you will need to call the API mutilple times. The API Server will randomly pick one of the ten responses and the responses will not be returned in the order in which you have added them