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Module 03 / Project 01 — First API Call

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— This project Walkthrough — Flashcards — —

Focus

  • Making a GET request with requests.get()
  • Understanding response objects (status code, headers, body)
  • Parsing JSON responses into Python dictionaries

Why this project exists

Before you can build anything that talks to the internet, you need to understand the basic request-response cycle. This project strips it down to the simplest possible case: fetch one resource, look at what comes back, and pull out the pieces you care about.

Run

cd projects/modules/03-rest-apis/01-first-api-call
python project.py

Expected output

--- Raw JSON response ---
{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}

--- Accessing individual fields ---
Status code : 200
Post ID     : 1
User ID     : 1
Title       : sunt aut facere repellat provident occaecati excepturi optio reprehenderit
Body preview: quia et suscipit...

--- Response headers (selected) ---
Content-Type: application/json; charset=utf-8

Alter it

  1. Change the URL to fetch post /posts/5 instead of /posts/1. Run again and compare the output.
  2. Print the full body field instead of just the first 20 characters.
  3. Add a line that prints the number of characters in the title.

Break it

  1. Change the URL to https://jsonplaceholder.typicode.com/posts/99999 (a post that does not exist). What status code do you get? What does response.json() return?
  2. Remove the .json() call and print response.text instead. What is the difference?
  3. Change the URL to an invalid domain like https://not-a-real-domain-xyz.com/posts/1. What error do you get?

Fix it

  1. Add a check: if response.status_code is not 200, print a warning and skip the JSON parsing.
  2. Wrap the requests.get() call in a try/except block that catches requests.exceptions.ConnectionError and prints a friendly message instead of a traceback.
  3. After fixing, run with both a valid and invalid URL to confirm both paths work.

Explain it

  1. What does response.json() actually do under the hood?
  2. What is the difference between response.text and response.json()?
  3. Why does requests.get() return a Response object instead of just the data?
  4. What HTTP method does requests.get() use, and what does that method mean?

Mastery check

You can move on when you can:

  • write a GET request from memory without looking at docs,
  • explain what a status code of 200 means vs 404,
  • extract any field from a JSON response,
  • describe the difference between .text and .json().

Next

Continue to Query Parameters.