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Text Generation

Last updated January 15, 2026

Use the OpenResponses API to generate text responses from AI models. The input array contains message objects with a role (user or assistant) and content field. The model processes the input and returns a response with the generated text.

generate.ts
const apiKey = process.env.AI_GATEWAY_API_KEY;
 
const response = await fetch('https://ai-gateway.vercel.sh/v1/responses', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    Authorization: `Bearer ${apiKey}`,
  },
  body: JSON.stringify({
    model: 'openai/gpt-5.2',
    input: [
      {
        type: 'message',
        role: 'user',
        content: 'Why do developers prefer dark mode?',
      },
    ],
  }),
});
 
const result = await response.json();

Response format

The response includes the generated text in the output array, along with token usage information.

{
  "id": "resp_abc123",
  "object": "response",
  "model": "openai/gpt-5.2",
  "output": [
    {
      "type": "message",
      "role": "assistant",
      "content": [
        {
          "type": "output_text",
          "text": "Habit and aesthetics reinforce the preference, but ergonomics and contrast are the primary drivers."
        }
      ]
    }
  ],
  "usage": {
    "input_tokens": 14,
    "output_tokens": 18
  }
}

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