Use OpenAI API in a Google Spreadsheets as an Apps Script function

script.js

function queryOpenAIChatCompletion(userMessage) {
  var apiKey = 'API_KEY'; // Replace with your actual API key
  var url = 'https://api.openai.com/v1/chat/completions';

  var payload = {
    model: "gpt-4o-mini",
    messages: [
      {"role": "user", "content": userMessage}
    ], 
    temperature: 0.4,
    max_tokens: 3000,
    top_p: 1,
    frequency_penalty: 0,
    presence_penalty: 0
  };

  var options = {
    'method' : 'post',
    'contentType': 'application/json',
    'headers': {
      'Authorization': 'Bearer ' + apiKey
    },
    'payload': JSON.stringify(payload)
  };

  try {
    var response = UrlFetchApp.fetch(url, options);
    var data = JSON.parse(response.getContentText());
    return data.choices[0].message.content; 
  } catch (e) {
    Logger.log(e.toString());
    return "Error: " + e.toString();
  }
}