---
title: "First API call in Python"
course: "AI103 · Prompting that works"
unit: "Building and choosing LLM systems"
lesson: 21 of 35
source: https://open.maestrocollege.edu/prompting-that-works/first-api-call-in-python
publisher: Maestro College
---

# First API call in Python

Lesson 21 of 35 in **Prompting that works** (AI103), unit "Building and choosing LLM systems". An open lesson from Maestro College.

## What the learner will be able to do
- Set up a Python project in VS Code with a virtual environment, an LLM provider's SDK, and an API key kept in a .env file that is never shared or committed.
- Write a script that sends a system message and a user message to a free-tier LLM API and prints the response text.
- Understand that the model keeps nothing between calls, so with a stateless chat API your code must resend the conversation history on every call to hold a conversation.

## Course teaching approach
- Start from a real-world problem, then introduce the concept as the solution.
- Keep it true beginner level, hands-on, a little gamified. The learner should feel they are winning.
- Balance explanation, demonstration and practice. No copy-paste exercises: give small story-based tasks.
- End with one fun closed question about the topic.

## How to use this document
You are acting as a tutor for a learner on Maestro Open. Teach from this document, one small step at a time. Ask the learner to try things, wait for their answer, then give feedback. Keep it beginner-friendly. If the lesson involves code or spreadsheets and you cannot run them, ask the learner to try it on their own computer and paste the result back. Do not award grades, credit or certificates.

## When the lesson is done
The lesson is complete only when the learner has shown they can do every outcome listed above. Check each one with a small task or question; if an answer is wrong, explain and let them try again before moving on.
When every outcome is covered:
1. Say clearly: "Lesson 21 complete: First API call in Python."
2. Give a two-line recap of what they learned.
3. Name the next lesson, "Token usage and API pricing" (lesson 22 of 35), and give the learner its link: https://open.maestrocollege.edu/prompting-that-works/token-usage-and-api-pricing.md. Tell them to paste that page into this chat, or fetch it yourself if you can open links, then start it the same way. Do not start teaching the next lesson's topic until the learner has it.

Previous lesson: Challenge: engineer a reliable prompt
Next lesson: Token usage and API pricing