Interactive API explorers in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this API explorer request?

You use an interactive API explorer to send a GET request to https://api.example.com/users/123. The response JSON is:

{"id":123,"name":"Alice","active":true}

What will the explorer show as the value of active?

A 1

B "true"

C True

D true

💡 Hint

Remember JSON boolean values are lowercase true or false.

The JSON boolean true is shown as true in the API explorer, not as a string or Python boolean.

🧠 Conceptual

intermediate

Which feature is typical of an interactive API explorer?

Choose the feature that best describes what an interactive API explorer does.

A Automatically generates API documentation from code comments.

B Compiles API code into executable binaries.

C Allows users to send API requests and see live responses in a user interface.

D Encrypts API requests for secure transmission.

💡 Hint

Think about what you do when you want to test an API endpoint interactively.

Interactive API explorers let you send requests and view responses live in a friendly interface.

🔧 Debug

advanced

Why does this API explorer request fail with a 401 error?

You use an interactive API explorer to send a POST request to /api/data with a JSON body. The server responds with 401 Unauthorized. You included the header Authorization: Bearer but left the token empty.

What is the most likely cause?

A The Authorization header is missing a valid token.

B The API explorer does not support POST requests.

C The JSON body is malformed and causes a server error.

D The API endpoint requires a GET request, not POST.

💡 Hint

401 means unauthorized. Check your authentication details.

An empty token in the Authorization header means the server rejects the request as unauthorized.

📝 Syntax

advanced

Which JSON body is valid for this API explorer POST request?

You want to send this JSON body in an API explorer POST request:

{"name": "Bob", "age": 30, "active": true}

Which option is a valid JSON string for the body?

A {name: "Bob", age: 30, active: true}

B {"name": "Bob", "age": 30, "active": true}

C {"name": "Bob", "age": "30", "active": "true"}

D {"name": "Bob", "age": 30, "active": True}

💡 Hint

JSON keys and string values must be in double quotes. Boolean values are lowercase.

Option B is valid JSON. Option B misses quotes on keys. Option B uses strings for numbers and booleans. Option B uses Python boolean True which is invalid in JSON.

🚀 Application

expert

How does an interactive API explorer handle pagination?

You use an interactive API explorer to fetch a list of items from an API that supports pagination with page and limit query parameters.

Which approach best describes how the explorer helps you get all items?

A It requires you to manually change the <code>page</code> parameter and resend requests.

B It automatically sends multiple requests incrementing <code>page</code> until no more items are returned.

C It ignores pagination and only shows the first page of results.

D It merges all pages into one response by modifying the API server.

💡 Hint

Think about what an explorer can do without custom automation.

Most interactive API explorers let you change query parameters manually and resend requests to see different pages.

Practice

1. What is the main purpose of an Interactive API explorer?

easy

A. To design user interfaces

B. To test APIs easily without writing code

C. To create database schemas

D. To write complex backend logic

Solution

1. Step 1: Understand the role of API explorers

   Interactive API explorers let users try API calls without coding, making testing simple.

2. Step 2: Compare with other options

   Writing backend logic, creating schemas, or designing UI are unrelated to API explorers.

3. Final Answer:

   To test APIs easily without writing code -> Option B

4. Quick Check:

   API explorers = test APIs without code [OK]

Hint: API explorers let you try APIs without coding [OK]

Common Mistakes:

• Confusing API explorers with coding tools
• Thinking they build UI or databases
• Assuming they generate backend code

2. Which of the following is the correct syntax to send a GET request in an interactive API explorer?

easy

A. GET /users

B. POST /users

C. PUT /users

D. DELETE /users

Solution

1. Step 1: Identify HTTP methods for requests

   GET is used to retrieve data, so GET /users requests user data.

2. Step 2: Eliminate other methods

   POST creates, PUT updates, DELETE removes data, so they are not for simple retrieval.

3. Final Answer:

   GET /users -> Option A

4. Quick Check:

   GET = retrieve data [OK]

Hint: GET method fetches data in API calls [OK]

Common Mistakes:

• Using POST instead of GET for fetching
• Confusing PUT or DELETE with GET
• Not specifying the HTTP method correctly

3. In an interactive API explorer, you send a POST request to /login with correct credentials. What is the expected response status code?

medium

A. 200 OK

B. 404 Not Found

C. 500 Internal Server Error

D. 401 Unauthorized

Solution

1. Step 1: Understand POST /login behavior

   POST /login with correct credentials usually returns 200 OK indicating success.

2. Step 2: Review other status codes

   404 means endpoint missing, 500 means server error, 401 means wrong credentials.

3. Final Answer:

   200 OK -> Option A

4. Quick Check:

   Successful login = 200 OK [OK]

Hint: Successful POST returns 200 OK status [OK]

Common Mistakes:

• Choosing 401 for correct credentials
• Confusing 404 with login failure
• Assuming server error on success

4. You try to send a request in an interactive API explorer but get a syntax error. Which of these is the most likely cause?

medium

A. Response status code is 200

B. Correct HTTP method but wrong endpoint URL

C. Server is down

D. Missing HTTP method before the endpoint

Solution

1. Step 1: Identify syntax error causes

   Syntax errors happen when the request format is wrong, like missing HTTP method.

2. Step 2: Differentiate from other issues

   Wrong URL causes 404 error, server down causes connection error, 200 means success.

3. Final Answer:

   Missing HTTP method before the endpoint -> Option D

4. Quick Check:

   Syntax error = missing method [OK]

Hint: Always include HTTP method before endpoint [OK]

Common Mistakes:

• Confusing syntax error with server errors
• Ignoring missing method in request
• Assuming 200 status means syntax is correct

5. You want to share an example API request and response with a teammate using an interactive API explorer. Which feature helps you do this most easily?

hard

A. Taking a screenshot of the API explorer window

B. Writing the API code manually in a text editor

C. Exporting the request and response as a shareable link

D. Copying only the request URL without headers or body

Solution

1. Step 1: Identify sharing features in API explorers

   Most interactive API explorers allow exporting requests and responses as shareable links.

2. Step 2: Compare other options

   Manual code writing or screenshots are less efficient; copying URL alone misses details.

3. Final Answer:

   Exporting the request and response as a shareable link -> Option C

4. Quick Check:

   Share API calls easily = export link [OK]

Hint: Use shareable links to send API examples [OK]

Common Mistakes:

• Thinking screenshots are best for sharing
• Copying only URL misses important data
• Writing code manually wastes time