Mastering GraphQL APIs with Postman

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GraphQL has emerged as a powerful technology for building flexible and efficient APIs. Postman is a leading API testing tool that supports GraphQL APIs, empowering developers to streamline their development workflow and ensure API functionality. In this comprehensive guide, we will explore how to leverage the latest version of Postman to work effectively with GraphQL APIs. Whether you’re new to GraphQL or an experienced developer, this guide will provide step-by-step instructions to get started and optimize your testing process.

But before that, please ensure you have installed the Postman and learned all the elements inside it. If not, kindly refer to our previous articles on Postman installation and testing APIs with Postman.

Table of contents

• Setting up Postman for GraphQL APIs
• Creating and configuring GraphQL API Requests
• Sending and inspecting GraphQL API requests
• Difference between GraphQL APIs and traditional APIs
• Conclusion

Setting up Postman for GraphQL APIs

• Click the plus sign at the top-left corner of the Postman interface.

• Select Collection and provide a descriptive name for your collection. Save the collection to finalize its creation.

• Click on the Environments Quick Look button at the top-right corner of the Postman window.

• Add a new environment and specify variables such as the API base URL, access tokens, or any other required parameters.

• Save the environment to make it available for use in your requests.

Creating and configuring GraphQL API Requests

Create a new request

• Click on the New button to add a new request to your collection.

• Provide a descriptive name for the request, reflecting the specific GraphQL operation you’ll be testing.

Set request method and URL

• Select the appropriate request method (usually POST) from the dropdown menu in the request builder
• Enter the GraphQL endpoint URL obtained from your API provider in the request URL field
• If you have defined environment variables for the base URL, enclose them in double curly braces, like {{base_url}}.

Set request headers

• Switch to the Headers tab in the request builder.
• Add any necessary headers, such as authorization or content type.
• Specify the key-value pairs for the headers, ensuring the correct format.

Construct the GraphQL query

• Move to the Body tab and select the GraphQL option.
• Utilize the syntax-highlighting editor to construct your GraphQL query or mutation.
• Ensure that your query adheres to the GraphQL syntax rules.

Add query variables (Optional)

• If your GraphQL operation requires variables, provide them in the request body.
• Click on the Pre-request Script tab in the request builder.
• Use JavaScript to set the necessary variables by accessing the pm. environment object. Example: pm.environment.set(“userId”, “12345”);

Sending and inspecting GraphQL API requests

Send the request

• Once you have set up the request, click the Send button to execute it.

• Postman will send the GraphQL query to the specified endpoint.

Inspect the response

• After sending the request, the response will appear in the Body section of the response panel.

• Explore the response body, headers, and status code to analyze the API’s behavior.
• Utilize response formatting options, such as JSON or HTML, for better readability.

Save and organize your requests

• To ensure reusability and easy access, save your requests within the collection.

• Create folders within the collection to categorize and organize related requests.

• Right-click on a request and select Save to choose the appropriate location within the collection.

Difference between GraphQL APIs and traditional APIs

Query flexibility

• GraphQL allows clients to request specific data by specifying the required fields, minimizing over-fetching and under-fetching data.
• Traditional APIs often return fixed data structures, potentially resulting in inefficient retrieval.

Reduced network requests

• GraphQL enables clients to retrieve multiple resources in a single request, reducing network roundtrips.
• Traditional APIs often require multiple requests to fetch related resources, leading to increased latency.

Versioning and schema evolution

• GraphQL APIs allow for seamless schema evolution and versioning, enabling clients to add or modify fields without breaking existing queries.
• Traditional APIs often require explicit versioning or cause disruptions when modifying the API schema.

Strongly typed schema

• GraphQL APIs have a strongly typed schema that explicitly defines available types, fields, and operations.
• Traditional APIs may lack formal type definitions, leading to documentation inconsistencies and potential errors.

Final thoughts on mastering GraphQL APIs with Postman

Postman empowers developers to work efficiently with GraphQL APIs, offering a range of features that streamline the testing and development process. By following the detailed steps outlined in this guide, you can leverage the latest version of Postman to master GraphQL API testing and ensure the functionality and reliability of your APIs.

Understanding the differences between GraphQL and traditional APIs helps you make informed decisions when choosing the appropriate technology for your projects. Whether performing manual testing or automating your tests, Postman provides the tools to optimize your GraphQL API testing process. Happy testing!

This post is part of our comprehensive Postman Mini-Course.