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Introduction
The GPT-3 API lets developers add AI to their apps. You do not need to train your own model. GPT-3 API is a paid service from OpenAI. This tutorial shows you how to get started. You will make your first API call in minutes.
What Is the GPT-3 API?
API stands for Application Programming Interface. It is a way for software to talk to GPT-3. You send text (a prompt). OpenAI’s servers process it. You get back a completion.
The API handles all the heavy computing. Your app just needs internet access.
For understanding GPT-3’s capabilities, see GPT-3 guide.
Prerequisites
- An OpenAI account (sign up at platform.openai.com)
- A credit card (API is pay-as-you-go)
- Basic programming knowledge (Python recommended)
Step 1: Get Your API Key
- Log into platform.openai.com
- Click on “API Keys” in the left menu
- Click “Create new secret key”
- Copy the key immediately (you cannot see it again)
- Store it safely (never share it publicly)
Step 2: Install the OpenAI Library
Open your terminal or command prompt. Run:
bash
pip install openai
For other languages (JavaScript, Java, etc.), see OpenAI’s documentation.
Step 3: Make Your First API Call
Create a Python file called first_gpt.py. Add this code:
python
import openai
openai.api_key = "your-api-key-here"
response = openai.Completion.create(
model="gpt-3.5-turbo-instruct",
prompt="Say this is a test",
max_tokens=20
)
print(response.choices[0].text)
Run the script. You should see “This is a test.”
For more prompt examples, read GPT-3 prompts.
Understanding Parameters
| Parameter | What It Does | Typical Value |
|---|---|---|
| model | Which GPT-3 version | “gpt-3.5-turbo-instruct” |
| prompt | Your input text | Any string |
| max_tokens | Max output length | 50–500 |
| temperature | Randomness (0–1) | 0.7 for creative, 0.2 for factual |
| top_p | Alternative to temperature | 1.0 |
Step 4: A Useful Example
This script writes a short story:
python
import openai
openai.api_key = "your-key"
prompt = "Write a 50-word story about a robot who learns to paint."
response = openai.Completion.create(
model="gpt-3.5-turbo-instruct",
prompt=prompt,
max_tokens=100,
temperature=0.8
)
print(response.choices[0].text)
Cost Considerations
GPT-3 API charges per token (about 0.75 words per token). Prices in 2026:
- GPT-3.5 Turbo: ~$0.001 per 1,000 tokens
- Older GPT-3 models: cheaper but less capable
For comparison with newer models, see GPT-3 vs GPT-4.
Common Errors and Fixes
| Error | Likely Cause | Fix |
|---|---|---|
| Rate limit | Too many requests | Slow down or upgrade plan |
| Invalid API key | Key typo or expired | Regenerate key |
| Insufficient quota | Out of credits | Add payment method |
| Model not found | Wrong model name | Check documentation |
Next Steps
- Build a chatbot
- Summarize long documents
- Generate product descriptions
- Analyze customer feedback
For more ideas, read GPT-3 use cases.
FAQ
1. Is the GPT-3 API free?
No. OpenAI gives $5 free credit to new users. After that, you pay.
2. Can I use GPT-3 API for commercial products?
Yes. OpenAI’s terms allow commercial use.
3. How fast is the API?
Usually 1–3 seconds per request. Slower for longer outputs.
4. Where can I get help?
OpenAI’s documentation or return to GPT-3 guide.
Conclusion
The GPT-3 API is easy to use. Get an API key, install the library, and make your first call in minutes. Experiment with parameters and prompts. Build amazing apps.
Next: GPT-3 vs GPT-4 or GPT-3 limitations.
