First API request and response in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an API request?

An API request is a message sent from a client to a server asking for some data or action. It usually includes a URL, method (like GET or POST), and sometimes data.

beginner

What does an API response contain?

An API response is the message the server sends back after receiving a request. It usually contains a status code (like 200 for success) and the data requested or a message.

beginner

What HTTP method is commonly used to get data from an API?

The GET method is used to ask the server to send data without changing anything on the server.

beginner

What does a 404 status code mean in an API response?

A 404 status code means the server could not find the requested resource or URL.

beginner

Why is JSON commonly used in API responses?

JSON is easy to read and write for both humans and computers. It is a simple text format that works well to send data between client and server.

Which HTTP method is used to retrieve data from an API?

A GET

B POST

C DELETE

D PUT

GET is the method used to request data without changing anything on the server.

What does a 200 status code in an API response mean?

A Resource not found

B Request successful

C Server error

D Unauthorized access

200 means the request was successful and the server sent back the data.

What format is commonly used to send data in API responses?

A JSON

B XML

C HTML

D CSV

JSON is the most common format because it is easy to read and write.

If you get a 404 status code, what does it mean?

A Success

B Bad request

C Server error

D Resource not found

404 means the server could not find the requested resource.

What part of an API request tells the server what action to perform?

A URL

B Headers

C HTTP method

D Body

The HTTP method (like GET or POST) tells the server what action to take.

Explain what happens when you make your first API request.

Think about the conversation between your app and the server.

Describe the role of status codes in API responses.

Status codes are like traffic lights for your request.

Practice

1. What does a GET request in an API usually do?

easy

A. It asks the server to send data back.

B. It sends data to the server to be saved.

C. It deletes data from the server.

D. It updates existing data on the server.

Solution

1. Step 1: Understand the GET method

   The GET method is used to request data from a server without changing it.

2. Step 2: Identify the purpose of GET in API

   GET asks the server to send data back to the client.

3. Final Answer:

   It asks the server to send data back. -> Option A

4. Quick Check:

   GET = Request data [OK]

Hint: GET means get data from server, no changes made [OK]

Common Mistakes:

• Confusing GET with POST or DELETE methods
• Thinking GET changes data on server
• Mixing up request and response roles

2. Which of these is the correct way to write a simple GET request URL?

easy

A. POST /api/data HTTP/1.1

B. DELETE /api/data HTTP/1.1

C. GET /api/data HTTP/1.1

D. PUT /api/data HTTP/1.1

Solution

1. Step 1: Identify HTTP methods

   GET is the method used to request data, so the request line must start with GET.

2. Step 2: Check the request format

   The correct format is "GET /path HTTP/1.1" for a GET request.

3. Final Answer:

   GET /api/data HTTP/1.1 -> Option C

4. Quick Check:

   GET request line starts with GET [OK]

Hint: GET requests start with GET keyword in HTTP line [OK]

Common Mistakes:

• Using POST, DELETE, or PUT instead of GET
• Wrong HTTP version or missing method
• Confusing request line with response line

3. Given this API response snippet:

{"status":200,"data":{"name":"Alice","age":30}}

What does the status code 200 mean?

medium

A. The request was unauthorized.

B. The requested resource was not found.

C. There was a server error processing the request.

D. The request was successful and data is returned.

Solution

1. Step 1: Understand HTTP status codes

   Status code 200 means the request succeeded and the server returned the requested data.

2. Step 2: Match status code to meaning

   200 is standard for success; 404 means not found, 500 means server error, 401 means unauthorized.

3. Final Answer:

   The request was successful and data is returned. -> Option D

4. Quick Check:

   Status 200 = Success [OK]

Hint: 200 means OK, request worked fine [OK]

Common Mistakes:

• Confusing 200 with error codes like 404 or 500
• Thinking 200 means no data returned
• Mixing status codes with data content

4. You send a GET request to an API but get no response. Which of these is a likely cause?

medium

A. The server returned status code 200.

B. The API endpoint URL is incorrect or misspelled.

C. You used the GET method instead of POST.

D. Your request included a valid Authorization header.

Solution

1. Step 1: Check the URL correctness

   If the URL is wrong or misspelled, the server won't respond properly or may not be found.

2. Step 2: Evaluate other options

   Using GET instead of POST may cause wrong data but usually gets a response; status 200 means success; valid Authorization helps access.

3. Final Answer:

   The API endpoint URL is incorrect or misspelled. -> Option B

4. Quick Check:

   Wrong URL = No response [OK]

Hint: Check URL spelling first if no response [OK]

Common Mistakes:

• Assuming method error causes no response
• Ignoring URL typos
• Confusing status codes with no response

5. You want to get user info from an API at https://api.example.com/users/123. Which is the best way to check if your request worked?

hard

A. Check if the response status code is 200 and the data contains user details.

B. Check if the request method was POST and the server returned 404.

C. Check if the response status code is 500 and the data is empty.

D. Check if the URL contains the word 'users' and the method is DELETE.

Solution

1. Step 1: Understand success criteria for API requests

   A successful GET request returns status 200 and the expected data.

2. Step 2: Evaluate options for correctness

   POST method and 404 means not found; 500 means server error; DELETE method is for removing data, not getting it.

3. Final Answer:

   Check if the response status code is 200 and the data contains user details. -> Option A

4. Quick Check:

   Status 200 + data = success [OK]

Hint: Success = status 200 + expected data [OK]

Common Mistakes:

• Confusing POST with GET for data retrieval
• Ignoring status codes meaning
• Checking wrong HTTP methods for GET requests