Testing Backend APIs with Postman

Testing Backend APIs with Postman

After successfully deploying your backend with API Gateway and Lambda, the next step is to test your APIs to verify that the backend system is functioning correctly before integrating with the frontend.

Postman is a powerful and widely-used tool that allows you to send requests (GET, POST, PUT, DELETE, …) to API endpoints, view responses, verify processing logic, and debug errors.

You can download Postman here: Download Postman

Objectives of this section:

  • Guide you on how to retrieve the API Gateway endpoint that you just deployed on AWS to use with Postman.
  • Practice sending GET/POST requests to the API, analyze the returned responses to verify backend correctness.
  • Identify and troubleshoot common errors encountered during API testing.

This section covers:

  1. Retrieving the API Gateway endpoint:
    Instructions on how to locate and copy the endpoint URL from the AWS Console for API testing purposes.
  2. Sending GET/POST requests to verify backend responses:
    Step-by-step guidance on how to send GET/POST requests with Postman, enter payload data, and review backend responses.

Note:
Before testing APIs with Postman, make sure that the backend has been deployed successfully and there are no errors from previous steps (CloudFormation/Lambda must be in a successful state).

By the end of this section, you will:

  • Know how to obtain the API Gateway endpoint for testing.
  • Be proficient in using Postman to send GET/POST requests to your backend.
  • Be able to analyze and verify API responses, and be ready to connect your tested backend with the frontend.

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