Tag campaign links so GA4 can tell where a visit came from

A UTM parameter is a query string on the end of the link itself. This tool installs nothing: as long as the destination page already runs standard GA4 tracking, the words after ? are what GA4 reads to file the visit under a campaign. The rules below decide whether the data is usable.

Pasted link	Parameters written
hoelee.com/promo	utm_source=facebook&utm_medium=paid_social&utm_campaign=raya-2026
hoelee.com/services?utm_source=old	utm_source=facebook&utm_medium=paid_social&utm_campaign=raya-2026
wa.me/60123456789	utm_source=facebook&utm_medium=paid_social&utm_campaign=raya-2026

• utm_source is the referrer, and it is not optional. facebook, google, newsletter — one value per platform. A link without a source cannot be attributed, so this tool refuses to build one and says why instead of handing over a link that will land in “Unassigned”.
• utm_medium is the channel, not the platform. paid_social, cpc, email, affiliate. Never write organic for a paid ad — that is the one label GA4 already uses for unpaid search traffic.
• utm_campaign is the campaign name (raya-2026, promo-55). utm_content separates two creatives, utm_term carries the paid keyword, utm_id carries your own campaign number and is the one parameter that survives a rename.
• Values are text. GA4 files Facebook and facebook as two different sources, so one typo splits a campaign in half. The lower-case switch folds every value; it is off by default because it rewrites what you typed.
• Existing parameters are preserved byte for byte. An affiliate id, a ref, a marketplace's own encoding keeps its position and its %2F. Only the six UTM parameters are touched — rewritten, or left alone if you choose “Keep them”.
• Never put customer data in a URL. A name, an email, a phone number or an IC number in a query string ends up in analytics, in server logs, in screenshots and in forwarded WhatsApp messages. Tag the campaign, not the person.
• Do not tag internal links. Clicking a tagged link starts a new session's campaign, so an internal link with UTMs on it overwrites the campaign that actually brought the visitor.
• Cap: 2,000 characters. Past that, chat apps and some ad networks truncate the link, so the tool refuses it rather than shipping half a link.

Parameters are written in a fixed order (source, medium, campaign, id, term, content), so two runs of the same campaign produce the same string and a diff between two exports means something.