Do I need an API key?

Yes, you need an OpenAI API key; the guide shows how to get and use one.

How does OpenAI API pricing work?

You pay per 1K tokens (input and output priced separately); cheaper models like gpt-4o-mini cost a fraction of flagship models. Set usage limits in the dashboard to avoid surprise bills, and cache repeated prompts to cut costs.

What is the difference between Chat Completions and the Responses API?

Chat Completions is the long-standing, widely-supported request/response format that virtually every tool understands. The newer Responses API adds built-in state, tools, and multi-step handling for agent-style apps. Start with Chat Completions for portability; adopt Responses when you want its native agent features.

GuideBeginner

The Complete OpenAI API Guide

Item: The Complete OpenAI API Guide
Rating: 4.8
Author: AI Resource Hub

A comprehensive, step-by-step guide to the OpenAI API ecosystem, covering GPT, DALL·E, and Whisper models in depth. It walks you through account setup, authentication, making your first API call, prompt design patterns, and cost optimisation strategies—ideal for developers new to the OpenAI platform who want a structured learning path.

Overview

"The Complete OpenAI API Guide" is a "Guide" resource curated by AI Resource Hub, filed under the AI APIs category and suited to Beginner-level learners. It is provided by AI Resource Hub, was last updated on 2026-07-02, and holds an editorial score of 4.8/5 from our team. Click "Visit Resource" on the right to open the original page.