REST vs SOAP vs GraphQL comparison in Rest API - Quick Revision & Key Differences

Recall & Review

beginner

What is REST in web services?

REST (Representational State Transfer) is an architectural style that uses standard HTTP methods like GET, POST, PUT, DELETE to interact with resources identified by URLs. It is simple, stateless, and uses JSON or XML for data exchange.

beginner

What does SOAP stand for and what is its main feature?

SOAP stands for Simple Object Access Protocol. It is a protocol that uses XML to define messages and relies on standards like WSDL for describing services. SOAP supports built-in error handling and is highly extensible.

intermediate

How does GraphQL differ from REST?

GraphQL lets clients request exactly the data they need in a single query, avoiding over-fetching or under-fetching. Unlike REST, which has multiple endpoints, GraphQL uses a single endpoint and flexible queries.

intermediate

Which API style is stateless and which can maintain state?

REST is stateless, meaning each request is independent and contains all needed information. SOAP can maintain state through WS-* standards, allowing more complex operations requiring session management.

beginner

What are the typical data formats used by REST, SOAP, and GraphQL?

REST commonly uses JSON or XML. SOAP strictly uses XML. GraphQL uses JSON for responses and a specific query language for requests.

Which API style uses a single endpoint for all queries?

A REST

B SOAP

C GraphQL

D None of the above

GraphQL uses a single endpoint to handle all queries, unlike REST which uses multiple endpoints.

Which protocol strictly uses XML for message format?

A SOAP

B GraphQL

C All of them

D REST

SOAP strictly uses XML for its message format.

Which API style is known for being stateless?

A SOAP

B REST

C GraphQL

D All maintain state

REST is stateless, meaning each request is independent.

Which API style allows clients to request exactly the data they need?

A GraphQL

B SOAP

C REST

D None

GraphQL allows clients to specify exactly what data they want in a query.

Which API style commonly uses multiple endpoints for different resources?

A All use single endpoint

B GraphQL

C SOAP

D REST

REST uses multiple endpoints, each representing a resource.

Explain the main differences between REST, SOAP, and GraphQL in terms of data format, endpoint usage, and state management.

Think about how each handles requests and data.

Describe a scenario where you might choose GraphQL over REST or SOAP.

Consider client data needs and network efficiency.

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