REST API calls with Invoke-RestMethod in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Invoke-RestMethod GET request?

Given the following PowerShell code that calls a public API, what will be the output?

PowerShell

Invoke-RestMethod -Uri 'https://api.agify.io?name=michael' | Select-Object -Property name,age

A Invoke-RestMethod : The remote server returned an error: (404) Not Found.

B @{name=undefined; age=69}

C @{name=michael; age=undefined}

D @{name=michael; age=69}

💡 Hint

The API returns predicted age for a given name in JSON format, which Invoke-RestMethod converts to a PowerShell object.

The API 'https://api.agify.io' predicts age for the name 'michael'. The output is a PowerShell object with properties 'name' and 'age'.

📝 Syntax

intermediate

Which option correctly sends a POST request with JSON body using Invoke-RestMethod?

You want to send a POST request with JSON data '{"username":"user1","password":"pass"}'. Which PowerShell command is correct?

A Invoke-RestMethod -Uri 'https://example.com/api/login' -Method POST -Body '{username:user1,password:pass}' -ContentType 'application/json'

B Invoke-RestMethod -Uri 'https://example.com/api/login' -Method POST -Body @{username='user1'; password='pass'} -ContentType 'application/json'

C Invoke-RestMethod -Uri 'https://example.com/api/login' -Method POST -Body '{"username":"user1","password":"pass"}' -ContentType 'application/json'

D Invoke-RestMethod -Uri 'https://example.com/api/login' -Method POST -Body '{"username":"user1","password":"pass"}'

💡 Hint

The body must be a JSON string and ContentType must be set to 'application/json'.

Option C correctly sends a JSON string as body with the proper content type. Option C sends a PowerShell hashtable which is not automatically converted to JSON. Option C has invalid JSON syntax. Option C misses ContentType, so server may reject.

🔧 Debug

advanced

Why does this Invoke-RestMethod call fail with a 401 Unauthorized error?

You run this command to access a protected API but get a 401 error: Invoke-RestMethod -Uri 'https://api.example.com/data' -Headers @{Authorization='Bearer mytoken123'} What is the most likely cause?

A The token 'mytoken123' is invalid or expired, causing the 401 Unauthorized error.

B The Authorization header key should be lowercase 'authorization' instead of 'Authorization'.

C Invoke-RestMethod does not support the -Headers parameter.

D The URI is missing the query parameter 'access_token=mytoken123'.

💡 Hint

401 Unauthorized means the server rejected the credentials.

The header name 'Authorization' is case-insensitive and correct. Invoke-RestMethod supports -Headers. The token is likely invalid or expired. The API expects the token in the Authorization header, not as a query parameter.

🚀 Application

advanced

How to extract the 'id' field from a JSON response using Invoke-RestMethod?

You run this command: $response = Invoke-RestMethod -Uri 'https://jsonplaceholder.typicode.com/posts/1' How do you get the 'id' value from $response?

A Get-Content $response.id

B $response.id

C $response->id

D $response['id']()

💡 Hint

Invoke-RestMethod converts JSON to a PowerShell object with properties.

You access properties of PowerShell objects with dot notation, so $response.id returns the 'id' value. Option B is invalid syntax. Option B is not PowerShell syntax. Option B tries to use Get-Content on a value, which is incorrect.

🧠 Conceptual

expert

What happens if you omit -ContentType when sending JSON data with Invoke-RestMethod POST?

You run this command: Invoke-RestMethod -Uri 'https://api.example.com/submit' -Method POST -Body '{"key":"value"}' What is the most likely result?

A The server may reject the request or treat the body as plain text, causing unexpected behavior.

B Invoke-RestMethod automatically detects JSON and sets ContentType to 'application/json'.

C The command will fail with a syntax error due to missing ContentType.

D The server will accept the request and parse the JSON correctly without ContentType.

💡 Hint

ContentType informs the server how to interpret the body data.

Without specifying -ContentType, the server may treat the body as plain text or default content type, leading to errors or ignored data. Invoke-RestMethod does not auto-set ContentType based on body content. The command runs but server behavior depends on ContentType header.