The OpenAI API Platform

The OpenAI API Platform#

Learning Objectives:

  • Navigate the OpenAI API platform and create API keys

  • Set spend limits to control costs

  • Track usage across models and projects

Platform Overview#

The OpenAI API platform at platform.openai.com is your control center for building with OpenAI models. It’s separate from ChatGPT — the platform is where you manage API keys, monitor usage, set budgets, and test models programmatically.

OpenAI API Platform Dashboard

The OpenAI API platform home page. The dashboard shows token usage, request counts, your monthly budget, and credit balance. The left sidebar organizes tools into Create (Chat, Agent Builder, Images) and Manage (Usage, API keys, Batches).

Key areas in the sidebar:

Section

What It Does

Chat

Test prompts interactively (like ChatGPT but with API parameters)

API keys

Create and manage your secret keys

Usage

Monitor spending, tokens, and requests

Batches

Track asynchronous batch processing jobs

Getting Started: API Keys#

To make API calls, you need an API key. Go to API keys in the left sidebar and click Create API key.

Important security rules:

  • Never commit API keys to git. Add .env to your .gitignore.

  • Store keys in environment variables or a .env file.

  • If a key is leaked, revoke it immediately from the platform.

The code examples in this course use python-decouple to load keys from a .env file at the repository root:

Full code: 02_openai_hello on GitHub

from decouple import Config, RepositoryEnv
from openai import OpenAI

# Load API key from .env file
config = Config(RepositoryEnv(".env"))
client = OpenAI(api_key=config("OPENAI_API_KEY"))

Your .env file should look like:

OPENAI_API_KEY=sk-proj-...

Setting a Spend Limit#

Before writing any code, set a monthly budget. In the dashboard screenshot above, notice the April budget: \(13.77 / \)450. This is a hard cap — once you hit it, API calls will fail rather than silently running up a bill.

To set your budget:

  1. Go to Settings (gear icon, top right)

  2. Navigate to Billing > Budgets

  3. Set a monthly limit

Why this matters: A single misplaced while True loop calling GPT-4o can burn through credits fast. A $10-50 monthly budget is plenty for coursework. You can always increase it later.

Tracking Usage#

The Usage page gives you a detailed breakdown of your API spending.

OpenAI API Platform Usage Page

The Usage page shows total spend, token counts, and request volume over time. You can filter by date range, project, and API capability. The breakdown by API capabilities (Responses and Chat Completions, Images, etc.) helps identify where your budget is going.

Key metrics to monitor:

  • Total Spend: Your dollar cost for the selected period

  • Total Tokens: Combined input + output tokens across all requests

  • Total Requests: Number of API calls made

  • Spend by capability: See if costs come from text generation, images, or other services

Model Pricing#

To estimate cost, multiply tokens by the model’s pricing:

Model

Input (per 1M tokens)

Output (per 1M tokens)

GPT-4o-mini

$0.15

$0.60

GPT-4o

$2.50

$10.00

GPT-4.1

$2.00

$8.00

GPT-4.1-mini

$0.40

$1.60

Tip

Start with gpt-4o-mini for development and testing. It’s fast and cheap. Only move to more expensive models once you’ve validated your approach works.

Key Takeaways#

  1. Set a budget first. Before writing any API code, configure a monthly spend limit on the platform. This protects you from runaway costs.

  2. Track usage. Use the platform’s Usage page to monitor spending by model, project, and date range.

  3. Start cheap, scale up. Use gpt-4o-mini during development. Move to larger models only after validating your approach.

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