Query parameters, fragments and what survives a redirect

The parts of a URL that behave differently

A URL has a scheme, a host, a path, a query string after the question mark, and a fragment after the hash. They are not equivalent in transit. The query string is sent to the server; the fragment is never sent to any server at all and exists only in the browser. That single distinction explains a surprising number of tracking bugs.

Parameter forwarding on the short link

Most platforms let you decide whether parameters added to the short link are passed through to the destination. With forwarding on, brand.co/sale?utm_content=header sends that parameter to the landing page, merged with any parameters the destination already had. With it off, the parameter is used for your own analytics and discarded.

Forwarding is useful when one short link is reused across placements with different content values. It is dangerous when the destination is a page that behaves differently based on unexpected parameters, so test with the real page.

Collisions between link parameters and destination parameters

If the destination already contains utm_source=email and the short link forwards utm_source=poster, one of them wins, and which one depends on the platform and sometimes on the analytics tag. Never rely on the tie-break. Decide where UTMs live — on the destination or on the short link — and be consistent.

Fragments and single-page applications

A fragment is preserved by the browser across a redirect in most cases, but it never reaches your server logs, so server-side analytics cannot see it. Applications that route on the fragment can also strip or rewrite the query string during their own initialisation, which is why a parameter visible in the address bar sometimes never reaches the analytics tag. Check what the tag receives, not what the address bar shows.

Encoding matters more than people expect

Ampersands, spaces and non-ASCII characters inside a parameter value must be percent-encoded. An unencoded ampersand inside a value silently splits it into two parameters, which is how campaign names end up truncated at the first word. Build URLs with a proper encoder rather than string concatenation.

Keep the query string short for shareable links

A destination carrying six tracking parameters looks untrustworthy when a person sees it in a status bar, and some chat platforms truncate long URLs in previews. This is a genuine advantage of putting the tracking on the short link's stored destination: the URL people see stays clean while the parameters still arrive.

Test the whole path, once, per channel

For each channel, click a real link on a real device and inspect the final URL at the landing page. In-app browsers, email click-trackers and locale redirects each drop parameters in their own way. Ten minutes of this per campaign type finds problems that would otherwise quietly corrupt a quarter of reporting.