Hey there, sorry to hear you're stuck on this—this discrepancy between Postman and Apps Script is super common, but let's walk through the most likely fixes based on what I've seen in similar issues:

• Mirror Postman's request headers exactly
  Postman automatically adds subtle headers you might miss in Apps Script, like Content-Type (critical for JSON payloads), Accept, or authorization tokens. Open Postman's "Headers" tab, copy every header except Postman-specific ones (like Postman-Token), and paste them into your UrlFetchApp options. For example:

  const requestOptions = {
    method: "PUT",
    headers: {
      "Content-Type": "application/json",
      "Authorization": "Bearer YOUR_AUTH_TOKEN",
      "Accept": "application/json"
      // Add all other headers from Postman here
    },
    payload: JSON.stringify(yourDataObject),
    muteHttpExceptions: true // This lets you see full error details
  };
  

• Double-check your payload formatting
  If you're sending JSON in Postman, make sure you're converting your Apps Script object to a string with JSON.stringify()—don't pass the raw object as the payload. For form-data or x-www-form-urlencoded payloads, you'll need to use Apps Script's multipart option instead of a simple payload string.

• Capture and debug the full error response
  Without seeing what the API is actually returning, you're guessing in the dark. Enable muteHttpExceptions: true (as in the example above) then log the response details:

  const response = UrlFetchApp.fetch("YOUR_API_URL", requestOptions);
  console.log("Status Code: " + response.getResponseCode());
  console.log("Error Details: " + response.getContentText());
  

  This will tell you if the API is rejecting your request for a specific reason (e.g., missing header, invalid payload, authorization failure).

• Verify authorization matches Postman
  If you're using OAuth2, Postman might handle token refreshes automatically—make sure your Apps Script code is using a valid, non-expired token (consider using Apps Script's OAuth2 library for easier management). For Basic Auth, encode your credentials properly:

  "Authorization": "Basic " + Utilities.base64Encode("username:password")
  

• Check for Apps Script-specific restrictions
  UrlFetchApp has default settings that might clash with some APIs. Try explicitly setting followRedirects: true (though it's default, sometimes forcing it helps) or validate if the API blocks Google's server IP ranges (rare, but possible—test with a different network if you can).

If you can share the error message from the logged response, a redacted snippet of your Apps Script code, and a screenshot of your Postman request setup (minus sensitive data), we can narrow this down even further.

内容的提问来源于stack exchange，提问作者Das Boomer