Click IDs and campaign tags are different animals
Most tracking parameters fall into two families. Campaign tags like the utm_ family are labels a marketer typed by hand: they say "this click came from the spring newsletter" and identify a campaign, not a person. Click IDs like gclid, fbclid and ttclid are different: a unique value generated for your individual click, used to match what you do on the site back to the exact ad impression you saw. One is a folder label. The other is a serial number on your click.
That difference is why the decoder shows two outputs. The cleaned link strips everything, which is what you want when sharing a link with another person. The canonical link keeps campaign tags but drops the per-person identifiers, which is what you want when saving a link for reuse without carrying someone else's click serial number along.
When stripping parameters breaks things
Not every parameter is surveillance. Some are load-bearing: a video ID, a search query, a page number, a timestamp. The decoder leaves parameters it cannot identify as trackers in place rather than guessing, and flags the ones it recognises with an explanation of what removing them changes. The practical rule: stripping recognised trackers never breaks the page for you, but it does break attribution for whoever sent the link, which is sometimes exactly the point and sometimes rude to a creator you like.
Links that carry their destination inside a parameter
Some links do not go where they say. Wrappers used by email tools, ad servers and some social platforms put the real destination inside a parameter of the visible URL, then bounce you through their counter on the way. When the decoder finds a parameter whose value is itself a URL, it surfaces the embedded destination so you can see where you would actually land, and go there directly if you prefer.
What survives a redirect and what doesn't
A redirect only keeps a query string if the service in the middle was built to forward it. Some shorteners and redirect chains explicitly re-append whatever arrived with the click onto their own destination URL; others redirect to a single fixed destination and silently drop everything that came in with it. There is no visible difference between the two until you test one: paste a tagged link into the decoder above, follow it through the redirect, and check what the landing page actually received on the far side.
Click IDs are the parameters most likely to go missing this way, since they are the ones a lazily-built redirect is least likely to have been designed to expect. If a link you are tracking loses its attribution somewhere between an ad and a landing page, a hop that doesn't forward query strings is one of the first places to look.
Which parameters are safe to strip before you share a link
Click IDs (fbclid, gclid, ttclid and the rest of that family) are the safest and most worth removing: they identify your specific click, they carry no benefit to whoever you're sending the link to, and stripping them costs nothing since the destination page loads exactly the same either way. Share tokens like igshid and si are the same story, harmless to strip, mildly identifying to keep. Email identifiers like mc_eid are worth removing by reflex, since they're a stable handle tied to your subscription rather than just your click.
Campaign tags (the utm_ family) are lower stakes, since they describe a campaign rather than a person, but stripping them is still reasonable if you're posting a link somewhere public and would rather not hand a stranger's marketing team free attribution data. What you should never strip on a guess is anything the decoder can't identify, a video timestamp, a page number, a search query. Those are functional, and removing them can change or break what loads.
The privacy reason to bother at all: a click ID combined with a platform's own logs is enough to tie a specific visit back to a specific account on platforms where you were logged in when you clicked. Passing that value along in a link you share hands the same trail to whoever you sent it to, and to anyone they forward it to after that.
What an unfamiliar parameter usually means
Most of the time, an unrecognised parameter isn't tracking at all. Sites build their own query parameters constantly for entirely mundane reasons: which tab was open, which variant of a page to render, a session token the page itself needs to work. The decoder's dictionary covers the tracking parameters common enough to be worth naming, but it can't know every parameter every site has ever invented, so anything outside that list is left exactly as it is rather than guessed at and possibly stripped. If a name matches a known prefix, an _id or _click style suffix, it gets flagged as a likely tracker even without an exact dictionary match; anything else is shown plainly, unexplained, and untouched.
A long parameter tail is not proof you're being tracked personally
A URL with a dozen parameters looks alarming, but length alone says nothing about what's actually being carried. Plenty of long tails are just verbose configuration: a page's rendering options, an encoded search filter, a data blob describing what to display, none of which identifies a person. What actually identifies you is a narrow set of specific parameters, the click-ID family, generated per click and matched against a platform's own logs, not the sheer number of characters in the URL. Paste the link into the decoder above and read what's actually named rather than judging by how messy it looks; a short URL carrying one gclid is more personally identifying than a long one full of harmless display settings.
What one click reveals
Every parameter this tool explains exists because a click is worth measuring. The parameter is only the label on the envelope; the click itself carries an IP address, and from it a location, network and device profile. Raydar is built on that fact: it gives you the receiving end, a per-click logbook of location, device and referrer for every visitor on your own links. If the decoder shows you what other companies attach to your clicks, Raydar shows you what your own clicks are worth.