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Mock API Response

Overview

The Yappes Mock API Response feature allows you to create simulated API endpoints that return predefined responses without connecting to actual backend services, so you can accelerate API development and testing cycles.

This powerful gateway policy enables you to prototype APIs before backend implementation is complete, test client applications against consistent responses, and demonstrate API functionality without exposing production systems.

The mocking capability integrates seamlessly into the Yappes API management workflow, offering flexible configuration options for request matching and response definition. You can create mock responses in two convenient ways: during the initial API onboarding process or directly from the gateway policy page.

This dual approach ensures that whether you're setting up a new API or enhancing an existing one, you can quickly implement mock responses that match your exact specifications. By leveraging Yappes mocking features, development teams can work in parallel - frontend developers can proceed with integration while backend services are still being developed, QA teams can test against predictable responses, and stakeholders can review API behavior through live demonstrations.

Prerequisites

Before implementing Mock API Responses on the Yappes platform, ensure you have:

  • Access Requirements

  • Valid Yappes platform account with API Manager access.

  • Appropriate permissions to create and manage gateway policies.

  • Rights to onboard and configure APIs.

  • Preliminary Setup

  • At least one API ready for onboarding (if using the onboarding method).

  • API hostname and host information configured.
  • Base path configuration
  • Domain preferences (custom or default)

Custom error and message

For error scenarios, you can override the default HTTP status code, error code, and message. See Custom Error and Message.

Step-by-Step Implementation

Method 1: Creating Mock API Response During API Onboarding

Step 1: Navigate to API Manager

  • Click on Manage APIs in the main dashboard.
  • Select My APIs from the submenu.
  • You should now see your API management interface.

Accessing My APIs

Step 2: Initiate API Onboarding

Step 3: Select Endpoint for attaching Mock API Response

  • Click on your newly created endpoint (e.g., get Post Data).
  • The endpoint details panel will open.

Accessing Endpoints

Step 4: Access Mock API Response Configuration

  • Locate and click the Mock API Response tab in the interface.
  • Click Create Mock API Response to open the policy configuration panel.
  • The Mock API Response configuration dialog will appear.

Access Mock API Response

Step 5: Create the Mock API Response Policy

  • Enter a descriptive name in the Policy Name field (e.g., Mocking Policy One).
  • Add a detailed description in the Enter description field to document the policy purpose.

Create Mock API Response

Step 6: Configure Request Matching Parameters

Define how incoming requests will be matched to trigger this mock response:

  • Parameter: Select the parameter type (e.g., Header)
  • Key: Enter the specific key to match (e.g., Server)
  • Operator: Choose the comparison operator (e.g., Equals)
  • Value: Specify the value that must match

Configure TLS Settings

Step 7: Define Mock API Response Configuration

Configure the response that will be returned:

  • Status Code: Set the HTTP status (e.g., 200)
  • Delay (ms): Add artificial delay if needed (e.g., 0):
  • Headers: Add custom response headers
  • Header Key: connection
  • Header Value: keep-alive
  • Body: Define the response body.

Configuring Destination Endpoint, Headers, Query Parameters and Path

Step 8: Submit to Create Mock API response

  • Review all configuration settings.
  • Click Submit to create the Mock API Response policy.
  • You’ll receive confirmation of the Mock API Response policy created and attached to the API endpoint.

Submit to Create Route

Method 2: Creating Mock API Response from Gateway Policy Page

Step 1: Navigate to Gateway Policies

  • Locate Gateway Control → Gateway Policies in the main navigation menu.
  • The policies management interface will display.

navigate to Gateway Policies

Step 2: Initialize New Policy Creation

  • Click + Create Policy button.
  • The policy creation modal will open.

Initialize New Policy Creation

Step 3: Configure Policy Settings

  • Set the Control Level to API Level.

  • In the Policy Type dropdown, select Mock API Response.

  • These settings determine the policy scope and functionality.

Configure Policy Settings

Step 4: Define Policy Details

  • Enter a unique Policy Name for identification.

  • Add a comprehensive Description of the policy purpose.

Step 5: Select Target API

  • From the available APIs list, select the API & Endpoint to attach the policy.

Select Target API

Step 6: Configure Request Matching Parameters

Define how incoming requests will be matched to trigger this mock response:

  • Parameter: Select the parameter type (e.g., Header)
  • Key: Enter the specific key to match (e.g., Server)
  • Operator: Choose the comparison operator (e.g., Equals)
  • Value: Specify the value that must match

Configure TLS Settings

Step 7: Define Mock API Response Configuration

Configure the response that will be returned:

  • Status Code: Set the HTTP status (e.g., 200)
  • Delay (ms): Add artificial delay if needed (e.g., 0):
  • Headers: Add custom response headers
  • Header Key: connection
  • Header Value: keep-alive
  • Body: Define the response body.

Configuring Destination Endpoint, Headers, Query Parameters and Path

Step 8: Submit to Create Mock API Response Policy

  • Review all policy configurations.
  • Click on Create Policy to save the configurations.
  • The policy will be active for the selected Endpoint of the API.

Create Mock API Response Policy

Mock Policy Configuration Panel

On Yappes, the Mock Response functionality in the API Manager allows you to configure simulated responses for APIs, enabling testing, validation, and debugging without invoking backend services.

The mock response interface consists of three main sections:

Policy Identification

  • Policy Name – Unique identifier for your mock response
  • Description – Optional field for documenting the mock's purpose
  • Status – Shows if the policy is active or inactive

Request Matching Section

  • Parameter Selector – Choose between Header, Query, Path, or Body parameters
  • Key Field – Specify the exact parameter key to match
  • Operator Dropdown – Select comparison logic (Equals, Contains, Regex)
  • Value Input – Define the expected value for matching

Response Definition Area

  • Status Code Field – HTTP status to return (100–599)
  • Delay Configuration – Artificial response delay in milliseconds
  • Headers Table – Add multiple response headers with key-value pairs
  • Body Editor – JSON or XML response body with syntax highlighting

ℹ️ Mock Policies are an effective way to simulate different API scenarios, helping you test success cases, errors, and edge conditions.

Advanced Configuration Tips

Key Takeaway: Configure multiple mock responses with different matching parameters to simulate various API scenarios – success cases, errors, and edge cases.

Common Configuration Patterns

  • Success Response Mock

  • Status: 200

  • Headers: Content-Type: application/json

  • Body: Valid JSON response

  • Error Response Mock

  • Status: 404 or 500

  • Headers: X-Error-Code: RESOURCE_NOT_FOUND

  • Body: Error message JSON

  • Delayed Response Mock

  • Status: 200
  • Delay: 3000 (3 seconds)
  • Use for timeout testing

Verification and Testing

Testing Your Mock Response

  • Send Test Request

  • Use Tryout on Yappes Platform or cURL

  • Include the matching parameters defined in your policy

  • Send request to your API endpoint

  • Verify Response

  • Check status code matches configuration
  • Validate headers are present
  • Confirm body content is correct

Success Indicators

  • Request logs show policy execution
  • Response matches all configured parameters
  • No error messages in gateway logs

Troubleshooting

Issue Possible Cause Solution
Mock response not triggering Request doesn't match parameters Verify exact parameter values and operators
Wrong status code returned Multiple policies conflicting Check policy priority and disable conflicting mocks
Response body is empty JSON formatting error Validate JSON syntax in body editor
Headers not appearing Header key formatting Ensure header keys follow HTTP standards
Excessive response time Delay set too high Reduce delay value or set to 0

Error Messages

  • "Policy matching failed"

  • Review request matching parameters

  • Check operator logic (Equals, Not Equals, Like)

  • Verify case sensitivity in values

  • "Invalid response configuration"

  • Validate JSON syntax in body
  • Ensure status code is valid (100–599)
  • Check header key-value format

Getting Help

If issues persist:

  • Check the gateway logs for detailed error messages
  • Verify API and policy status are both active
  • Contact Yappes support with policy name and error details