Free tools
Six tools, no account
Four of them fetch a URL the way a paid click arrives — as an iPhone, following every redirect — and tell you what came back. Two do arithmetic on your own numbers. Each one says what it cannot answer, because the check nobody ran is the one that costs money.
a free one-off check of any URL — redirect chain, status, soft-404 wording, response size. Names the three checks one request cannot perform.
Cannot: It knows about this minute. Nothing is watching afterwards.
the full hop chain for a URL — or a list of ten — and whether each click still lands on the path you registered.
Cannot: A chain that is right today can be rewritten by tonight’s deploy.
what a phone is actually served, which is where most paid clicks come from and where consent walls and app interstitials only fire.
Cannot: It reads what the server sent a phone. It does not render the page, so it cannot judge tap targets or layout shift.
the failure this exists for, and the one variant we cannot see.
Cannot: It matches the phrases the product matches. A page that says it is gone in words nobody uses will pass.
customer acquisition cost from your own spend and conversions, with no assumed benchmark supplied for you.
Cannot: Arithmetic on figures you supply. It does not know whether the customers were worth acquiring.
minutes broken times spend rate, on your numbers. No counterfactual revenue in it.
Cannot: Minutes times a spend rate. It claims no revenue you would have earned.
What they have in common
They all answer about this minute.
Every fault these find is one you would have found the first time you looked. The expensive version is the one that starts at midnight on a page that was fine yesterday, while the campaign keeps paying for clicks into it — which is the difference between checking and monitoring, and what it costs.
Nothing you paste is stored. The checkers keep the verdicts and not the URL, to count how often paid destinations are broken; the calculators run entirely in your browser and send nothing at all. The taxonomy behind the verdicts is published as a CC BY 4.0 dataset, and one day’s measurement of real ad destinations as another.