GraphQL body in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the GraphQL body in a Postman request?

The GraphQL body contains the query or mutation that specifies exactly what data you want to fetch or change from the GraphQL server.

beginner

How do you format a GraphQL body in Postman?

You format it as a JSON object with a "query" field containing your GraphQL query string, and optionally a "variables" field for dynamic values.

beginner

Example of a simple GraphQL query body in Postman?

{ "query": "{ user(id: \"1\") { name email } }" } This fetches the name and email of the user with id 1.

intermediate

Why use variables in a GraphQL body?

Variables let you reuse queries with different inputs without changing the query string, making tests cleaner and easier to maintain.

beginner

What content type should you set in Postman when sending a GraphQL body?

Set the Content-Type header to "application/json" because the GraphQL body is sent as a JSON object.

What key must be included in the JSON body to send a GraphQL query in Postman?

A "query"

B "request"

C "body"

D "data"

The GraphQL query must be inside the "query" key in the JSON body.

How do you include variables in a GraphQL request body?

A In the HTTP headers

B Inside the "query" string directly

C Inside the "variables" key as a JSON object

D In the URL parameters

Variables are passed as a JSON object inside the "variables" key in the request body.

Which HTTP method is typically used to send a GraphQL body in Postman?

A POST

B GET

C PUT

D DELETE

GraphQL queries and mutations are usually sent using POST requests.

What Content-Type header should you set for a GraphQL request in Postman?

A text/plain

B application/json

C application/graphql

D multipart/form-data

GraphQL requests in Postman are sent as JSON, so Content-Type should be application/json.

Why is it better to use variables in GraphQL queries?

A To send queries faster

B To make the query longer

C To bypass authentication

D To avoid repeating the same query with different values

Variables let you reuse the same query with different inputs, making tests simpler and cleaner.

Explain how to structure a GraphQL body in Postman for a query with variables.

Think about how to separate the query and the dynamic data.

Describe the steps to test a GraphQL API using Postman.

Consider what you need to prepare before sending the request.

Practice

1. What is the main purpose of the query field in a GraphQL body when testing with Postman?

easy

A. To list all available API endpoints

B. To define the HTTP headers for the request

C. To set the URL of the GraphQL endpoint

D. To specify the exact data you want to fetch or mutate from the API

Solution

1. Step 1: Understand the role of the query field

   The query field contains the GraphQL query or mutation string that tells the API exactly what data to return or change.

2. Step 2: Differentiate from other request parts

   Headers and URLs are set elsewhere in Postman; the query field is specifically for the GraphQL operation.

3. Final Answer:

   To specify the exact data you want to fetch or mutate from the API -> Option D

4. Quick Check:

   GraphQL query = data request [OK]

Hint: Remember: query means what data you want [OK]

Common Mistakes:

• Confusing query with HTTP headers
• Trying to put URL or endpoint inside query
• Leaving query empty or missing

2. Which of the following is the correct minimal structure of a GraphQL body in Postman?

easy

A. { "query": "{ user { id name } }" }

B. { "url": "https://api.example.com/graphql" }

C. { "headers": { "Content-Type": "application/json" } }

D. { "variables": { "id": 1 } }

Solution

1. Step 1: Identify the required fields in a GraphQL body

   The minimal GraphQL body must have a query field with a valid query string.

2. Step 2: Check each option

   { "query": "{ user { id name } }" } correctly shows a JSON object with a query string. The structures with "url" and "headers" are for other parts of the Postman request, not the body. { "variables": { "id": 1 } } only has variables without a query, which is invalid.

3. Final Answer:

   { "query": "{ user { id name } }" } -> Option A

4. Quick Check:

   GraphQL body needs query string [OK]

Hint: GraphQL body always needs a query string [OK]

Common Mistakes:

• Putting URL or headers inside the GraphQL body
• Sending variables without a query
• Using invalid JSON format

3. Given this GraphQL body in Postman:

{
  "query": "query getUser($id: ID!) { user(id: $id) { name email } }",
  "variables": { "id": "123" }
}

What data will the API return if user 123 exists?

medium

A. Only the user's ID

B. The user's name and email fields

C. An error because variables are not allowed

D. All users' names and emails

Solution

1. Step 1: Understand the query and variables

   The query requests name and email of a user with a specific id passed as a variable.

2. Step 2: Interpret the expected response

   Since id is set to "123", the API will return the name and email of user 123 if they exist.

3. Final Answer:

   The user's name and email fields -> Option B

4. Quick Check:

   Variables filter data = user 123 info [OK]

Hint: Variables customize queries to fetch specific data [OK]

Common Mistakes:

• Ignoring variables and expecting all users
• Thinking variables cause errors in GraphQL
• Expecting ID field in response without requesting it

4. You send this GraphQL body in Postman:

{
  "query": "query getUser($id: ID!) { user(id: $id) { name email } }"
}

The API returns an error about missing variables. What is the fix?

medium

A. Add a variables field with the required id value

B. Remove the $id variable from the query

C. Change the query to a mutation

D. Add HTTP headers for authentication

Solution

1. Step 1: Identify the cause of the error

   The query requires a variable $id but no variables field was sent, so the API complains about missing input.

2. Step 2: Fix by adding variables

   Include a variables JSON object with the id value, e.g., { "id": "123" }, to satisfy the query requirement.

3. Final Answer:

   Add a variables field with the required id value -> Option A

4. Quick Check:

   Variables must match query parameters [OK]

Hint: Always send variables if query requires them [OK]

Common Mistakes:

• Forgetting to send variables when query uses them
• Trying to remove variables from query without adjusting logic
• Assuming authentication fixes variable errors

5. You want to test a GraphQL mutation to update a user's email using variables in Postman. Which GraphQL body correctly uses variables for this mutation?

hard

A. { "query": "mutation updateUser { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": 456, "email": "[e-mail]" } }

B. { "query": "mutation { updateUser(id: 456, email: \"[e-mail]\") { id email } }" }

C. { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } }

D. { "query": "mutation updateUser($id, $email) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } }

Solution

1. Step 1: Check variable declarations in mutation

   Variables must be declared with types and exclamation marks for required fields, e.g., $id: ID!, $email: String!.

2. Step 2: Verify variables usage and JSON format

   { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } correctly declares variables with types and passes matching variables in JSON. { "query": "mutation { updateUser(id: 456, email: \"[e-mail]\") { id email } }" } hardcodes values without variables. { "query": "mutation updateUser { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": 456, "email": "[e-mail]" } } misses variable types. { "query": "mutation updateUser($id, $email) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } misses exclamation marks in variable types.

3. Final Answer:

   { "query": "mutation updateUser($id: ID!, $email: String!) { updateUser(id: $id, email: $email) { id email } }", "variables": { "id": "456", "email": "[e-mail]" } } -> Option C

4. Quick Check:

   Declare variables with types and pass matching values [OK]

Hint: Declare variables with types and pass matching JSON values [OK]

Common Mistakes:

• Omitting variable types or exclamation marks
• Using variables without declaring them
• Hardcoding values instead of using variables