Google's Campaign URL Builder is enough for one URL. UTM Canon is for the spreadsheet job: paste a CSV of url, source, medium, campaign, enforce lowercase-hyphen names, and download the tagged URLs. Nothing is uploaded. Building stays on your device. Free: 25 URLs, including download — enough to finish one campaign. Pro: ¥4,900 for 12 months of larger bulk plus locked taxonomy. Not a $19/mo seat.