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1. Make a Google Sheet (or use an existing one) — add a header row with whatever columns you want, e.g. Date, Property, Platform, Market, Units, Price, Broker, Stage, Category, Contacts, Notes.
2. In that Sheet, go to Extensions → Apps Script, delete the placeholder code, and paste in the script below.
3. Click Deploy → New deployment, type = Web app, "Execute as" = Me, "Who has access" = Anyone. Click Deploy and authorize it (it's your own script, in your own account).
4. Copy the Web app URL it gives you and paste it into the field above, then Save Connection.

function doPost(e) {
  const sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  const data = JSON.parse(e.postData.contents);
  const headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
  const row = headers.map(h => data[h] !== undefined ? data[h] : '');
  sheet.appendRow(row);
  return ContentService.createTextOutput(JSON.stringify({ok:true})).setMimeType(ContentService.MimeType.JSON);
}