OpenAI Has a Free Tier API — Build a Chatbot in 10 Lines of Python

#ai #python #discuss #beginners

OpenAI gives you free API credits when you sign up. Here is how to build a working chatbot in 10 lines.

The Complete Code

from openai import OpenAI

client = OpenAI()  # uses OPENAI_API_KEY env var

print('Chat with AI (type "quit" to exit)')
history = [{'role': 'system', 'content': 'You are a helpful assistant.'}]

while True:
    user_input = input('You: ')
    if user_input.lower() == 'quit':
        break
    history.append({'role': 'user', 'content': user_input})
    response = client.chat.completions.create(model='gpt-3.5-turbo', messages=history)
    reply = response.choices[0].message.content
    history.append({'role': 'assistant', 'content': reply})
    print(f'AI: {reply}')

Setup (3 minutes)

pip install openai
export OPENAI_API_KEY='your_key_here'
python chatbot.py

Get your key at platform.openai.com/api-keys. Free tier gives you enough credits for thousands of messages.

Make It Useful: Specialized Bots

Change the system message to create specialized assistants:

# Code reviewer
system = 'You are a senior Python developer. Review code for bugs, performance, and style.'

# SQL helper  
system = 'You are a SQL expert. Convert natural language questions to SQL queries.'

# Writing assistant
system = 'You are an editor. Improve the clarity and conciseness of any text.'

Add Streaming (Feels More Natural)

stream = client.chat.completions.create(
    model='gpt-3.5-turbo',
    messages=history,
    stream=True
)

for chunk in stream:
    content = chunk.choices[0].delta.content or ''
    print(content, end='', flush=True)
print()

Tokens appear one by one, like someone typing.

Cost

GPT-3.5-turbo: ~$0.002 per 1K tokens
Average message: ~100 tokens
1000 messages: ~$0.20

You can chat for months on the free credits.

What would you build with the OpenAI API?

Beyond chatbots — summarizers, translators, code generators, email writers. What is your use case?

I write about APIs, AI, and Python automation. Follow for weekly tutorials.

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