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The Responses API is where OpenAI puts stateful conversations, multimodal inputs, tools, and structured outputs. Learn the shape before you build.
Chat Completions taught a generation of developers the messages array. The Responses API is the newer shape: it supports text and image inputs, text outputs, conversation state, built-in tools, and function calling in one API.
import OpenAI from "openai";
const client = new OpenAI();
const response = await client.responses.create({
model: "gpt-5.5",
instructions: "Be concise and verify assumptions.",
input: "Draft an incident-summary template for a failed deploy.",
});
console.log(response.output_text);The simplest Responses call still looks like a normal model request.| Use Chat Completions when | Use Responses when |
|---|---|
| You maintain a stable legacy chat app | You need built-in tools or multimodal workflows |
| You cannot migrate everything yet | You need conversation state without rebuilding threads |
| The endpoint is already working and low risk | You are starting a new OpenAI integration |
| You only need simple message in, text out | You need structured output, tools, or future agent features |
The big idea: new OpenAI apps should usually start with Responses, while old apps should migrate where the newer surface pays for itself.
15 questions · take it digitally for instant feedback at tendril.neural-forge.io/learn/quiz/end-openai-responses-api-creators
What is the core idea behind "The Responses API: OpenAI's Modern Developer Surface"?
Which term best describes a foundational idea in "The Responses API: OpenAI's Modern Developer Surface"?
A learner studying The Responses API: OpenAI's Modern Developer Surface would need to understand which concept?
Which of these is directly relevant to The Responses API: OpenAI's Modern Developer Surface?
Which of the following is a key point about The Responses API: OpenAI's Modern Developer Surface?
Which of these does NOT belong in a discussion of The Responses API: OpenAI's Modern Developer Surface?
What is the key insight about "Migration can be incremental" in the context of The Responses API: OpenAI's Modern Developer Surface?
What is the key insight about "Review date" in the context of The Responses API: OpenAI's Modern Developer Surface?
Which statement accurately describes an aspect of The Responses API: OpenAI's Modern Developer Surface?
What does working with The Responses API: OpenAI's Modern Developer Surface typically involve?
Which best describes the scope of "The Responses API: OpenAI's Modern Developer Surface"?
Which of the following is a concept covered in The Responses API: OpenAI's Modern Developer Surface?
Which of the following is a concept covered in The Responses API: OpenAI's Modern Developer Surface?
Which of the following is a concept covered in The Responses API: OpenAI's Modern Developer Surface?
Which of the following is a concept covered in The Responses API: OpenAI's Modern Developer Surface?