REST vs SOAP vs GraphQL comparison in Rest API

Introduction

APIs help different programs talk to each other. REST, SOAP, and GraphQL are three ways to build these APIs. Knowing their differences helps you pick the best one for your project.

You want a simple and fast way to get or send data over the internet.

You need strict rules and security for exchanging messages between systems.

You want clients to ask for exactly the data they need, no more, no less.

You are building a mobile app that needs to reduce data usage.

You want to connect many different services with flexible queries.

Syntax

Rest API

REST:
- Uses URLs (endpoints) to access resources.
- Uses HTTP methods like GET, POST, PUT, DELETE.
- Data usually in JSON format.

SOAP:
- Uses XML messages.
- Has a strict message format with envelope and headers.
- Uses protocols like HTTP, SMTP.

GraphQL:
- Uses a single endpoint.
- Clients send queries specifying exactly what data they want.
- Data returned in JSON format.

REST is easy to use and popular for web APIs.

SOAP is more formal and used in enterprise systems needing high security.

Examples

Get user with ID 123 using REST.

Rest API

REST example:
GET /users/123
Response: {"id":123, "name":"Alice"}

SOAP message to get user 123.

Rest API

<Envelope>
  <Body>
    <GetUser>
      <UserId>123</UserId>
    </GetUser>
  </Body>
</Envelope>

GraphQL query to get user 123's id and name.

Rest API

GraphQL example:
query {
  user(id: 123) {
    id
    name
  }
}

Sample Program

This program shows how REST, SOAP, and GraphQL requests look. It fetches user data with REST, shows a SOAP message, and a GraphQL query.

Rest API

import requests

# REST example: Get user data
rest_response = requests.get('https://jsonplaceholder.typicode.com/users/1')
print('REST response:', rest_response.json())

# SOAP example: Simple SOAP request (mocked as string here)
soap_request = '''
<Envelope>
  <Body>
    <GetUser>
      <UserId>1</UserId>
    </GetUser>
  </Body>
</Envelope>
'''
print('SOAP request:', soap_request.strip())

# GraphQL example: Query user data
graphql_query = '''
query {
  user(id: 1) {
    id
    name
  }
}
'''
print('GraphQL query:', graphql_query.strip())

Important Notes

REST is usually faster and easier to use but less strict.

SOAP has built-in error handling and security but is more complex.

GraphQL reduces over-fetching data but needs more setup on the server.

Summary

REST uses simple URLs and HTTP methods to work with resources.

SOAP uses XML and strict message formats for secure communication.

GraphQL lets clients ask for exactly the data they want in one request.

Practice

1. Which API style allows clients to request exactly the data they need in a single query?

easy

A. FTP

B. REST

C. SOAP

D. GraphQL

Solution

1. Step 1: Understand GraphQL's data fetching

   GraphQL lets clients specify exactly which fields they want in a query, reducing over-fetching.

2. Step 2: Compare with REST and SOAP

   REST uses fixed endpoints and HTTP methods, SOAP uses strict XML messages, neither allows flexible data selection like GraphQL.

3. Final Answer:

   GraphQL -> Option D

4. Quick Check:

   Exact data request = GraphQL [OK]

Hint: GraphQL = precise data queries in one request [OK]

Common Mistakes:

• Confusing REST with GraphQL's flexible queries
• Thinking SOAP supports flexible data selection
• Choosing unrelated protocols like FTP

2. Which of the following is the correct HTTP method typically used by REST APIs to update a resource?

easy

A. PUT

B. POST

C. GET

D. CONNECT

Solution

1. Step 1: Recall REST HTTP methods

   REST commonly uses PUT to update or replace a resource at a URL.

2. Step 2: Differentiate from other methods

   GET retrieves data, POST creates new resources, CONNECT is for network tunnels, so only PUT updates.

3. Final Answer:

   PUT -> Option A

4. Quick Check:

   Update resource = PUT [OK]

Hint: PUT method updates resources in REST [OK]

Common Mistakes:

• Using GET to update data
• Confusing POST with update instead of create
• Selecting non-REST HTTP methods like CONNECT

3. Given the following GraphQL query, what data will the client receive?

{ user(id: "123") { name email } }

medium

A. {"user": {"name": "Alice"}}

B. {"user": {"name": "Alice", "email": "[e-mail]"}}

C. {"user": {"id": "123", "name": "Alice"}}

D. {"user": {"email": "[e-mail]"}}

Solution

1. Step 1: Analyze the GraphQL query fields

   The query requests the user's name and email fields for user with id "123".

2. Step 2: Determine expected response

   The response includes both requested fields inside the user object, matching {"user": {"name": "Alice", "email": "[e-mail]"}}.

3. Final Answer:

   {"user": {"name": "Alice", "email": "[e-mail]"}} -> Option B

4. Quick Check:

   Requested fields = name and email [OK]

Hint: GraphQL returns only requested fields in response [OK]

Common Mistakes:

• Expecting all user fields returned
• Missing one of the requested fields
• Confusing id field presence

4. You have a SOAP API call that fails due to incorrect message format. What is the most likely cause?

medium

A. Using GraphQL query syntax in the request

B. Missing HTTP GET method in the request

C. Using JSON instead of XML in the request body

D. Not specifying the resource URL correctly

Solution

1. Step 1: Understand SOAP message format requirements

   SOAP requires XML formatted messages strictly following its schema.

2. Step 2: Identify common format errors

   Sending JSON instead of XML breaks the SOAP message format, causing failure.

3. Final Answer:

   Using JSON instead of XML in the request body -> Option C

4. Quick Check:

   SOAP needs XML, not JSON [OK]

Hint: SOAP messages must be XML formatted [OK]

Common Mistakes:

• Using JSON payloads with SOAP
• Confusing HTTP methods for SOAP
• Mixing GraphQL syntax with SOAP

5. You need to design an API for a mobile app that requires minimal data usage and flexible queries. Which API style is best and why?

hard

A. GraphQL, because it lets clients request exactly the data they need

B. REST, because it uses simple URLs and HTTP methods

C. SOAP, because it uses strict XML for secure communication

D. FTP, because it transfers files efficiently

Solution

1. Step 1: Identify requirements for minimal data and flexible queries

   The app needs to reduce data usage and allow clients to specify data fields.

2. Step 2: Match API styles to requirements

   GraphQL allows clients to request only needed data in one query, minimizing data transfer and providing flexibility.

3. Final Answer:

   GraphQL, because it lets clients request exactly the data they need -> Option A

4. Quick Check:

   Minimal data + flexible queries = GraphQL [OK]

Hint: Choose GraphQL for flexible, minimal data queries [OK]

Common Mistakes:

• Choosing REST without flexible data selection
• Selecting SOAP despite heavy XML overhead
• Confusing FTP with API styles