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How To Use Graphiql With Postman

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Using GraphiQL with Postman for Efficient GraphQL API Testing

GraphiQL is a powerful GraphQL IDE that provides an intuitive interface for exploring and testing GraphQL APIs. While GraphiQL is a fantastic tool for development, Postman offers a broader range of features for comprehensive API testing. This guide will show you how to leverage the power of both tools to streamline your GraphQL API testing workflow.

Step 1: Setting up a GraphQL API

Before we begin, let’s ensure you have a GraphQL API running. You can either use a public GraphQL API or set up your own. Here’s an example using a public API:

Step 2: Creating a Postman Collection

  1. Open Postman: Launch the Postman app and create a new collection. Choose a descriptive name like “GraphQL API Testing.”

  2. Add a Request: Click the “Add Request” button and give your request a relevant name, e.g., “Get Countries.”

Step 3: Configuring the Request

  1. Set the Method: Select POST as the HTTP method for your request.

  2. Set the URL: Enter the URL of your GraphQL endpoint. For our example, use https://countries.trevorblades.com/.

  3. Specify Headers: Add a header called Content-Type with the value application/json.

Step 4: Crafting your GraphQL Query

  1. Create a JSON Body: In the request body, create a JSON object with a top-level field named query. This field will contain your GraphQL query.

  2. Example Query:

    {
      "query": "query {
        countries {
          name
          code
          continent {
            name
          }
        }
      }"
    }

    This query retrieves the country names, codes, and continent information.

Step 5: Sending the Request and Inspecting the Response

  1. Send the Request: Click the “Send” button in Postman to send your GraphQL query to the API.

  2. Inspect the Response: Postman will display the API response, providing you with data in a JSON format. Analyze the response to verify that the data is returned correctly and meets your expectations.

Step 6: Using Variables and Mutations

Postman allows you to work with variables and mutations, enhancing your GraphQL testing.

  1. Defining Variables: Define variables in your JSON body to parameterize your queries.

    {
      "query": "query getCountry($code: String!) {
        country(code: $code) {
          name
          capital
        }
      }",
      "variables": {
        "code": "US"
      }
    }

  2. Mutations: For operations that modify data, use mutations.

    {
      "query": "mutation addCountry($name: String!, $code: String!) {
        addCountry(name: $name, code: $code) {
          name
          code
        }
      }",
      "variables": {
        "name": "New Zealand",
        "code": "NZ"
      }
    }

Step 7: Utilize GraphiQL for Query Exploration

While Postman is ideal for automated testing, GraphiQL excels in interacting with the GraphQL API and exploring its capabilities.

  1. Access GraphiQL: Many GraphQL APIs provide a built-in GraphiQL interface. If not, some third-party tools like Insomnia allow you to access GraphiQL.

  2. Experiment with Queries: Use GraphiQL to experiment with different queries, explore nested relationships, and understand the structure of your API.

  3. Utilize Autocompletion: GraphiQL offers autocompletion suggestions, making it easier to write complex queries.

Integrating GraphiQL with Postman

While Postman and GraphiQL serve distinct purposes, you can seamlessly integrate them:

  • Query Exploration: Use GraphiQL to experiment with queries and then copy the validated query to your Postman request.
  • Schema Understanding: Explore your API schema in GraphiQL to understand field names and types, enhancing your Postman tests.

Conclusion

Combining Postman’s testing capabilities with GraphiQL’s exploration features empowers you to confidently test and interact with your GraphQL APIs. This approach ensures thorough testing, helps you understand your API, and accelerates your development process.

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