The Markup's Privacy Tool Now Detects TikTok and X Trackers

The Markup says its privacy tool can now tell users whether TikTok and X are tracking them across the internet — a shift that puts two of the most-watched platforms squarely inside a journalist-built transparency project.

The announcement, made by the nonprofit newsroom, expands what its tool surfaces to ordinary users: whether trackers tied to TikTok and X follow them as they browse beyond the platforms themselves. Until now, questions about cross-site tracking by these companies have relied heavily on academic research, regulatory filings, and browser-level debugging that most people cannot perform.

That gap matters for social media practitioners. Advertisers and creators plan campaigns on the assumption that platform pixels and embedded widgets collect data on third-party sites, feeding it back into ad targeting and measurement systems. A public tool that flags this behavior gives agencies, brand teams, and privacy-conscious publishers a concrete way to check what TikTok and X actually collect — not just what their policies say they collect.

The distinction is significant. Platform privacy policies describe data practices in broad terms, and enforcement varies by jurisdiction. TikTok in particular has faced sustained regulatory pressure in the United States and Europe over data collection and its links to parent company ByteDance. X, under Elon Musk's ownership, has restructured its ad products and data partnerships, leaving practitioners with less certainty about how its tracking infrastructure has changed. The Markup's tool does not adjudicate those debates, but it gives users an observable signal.

For social teams, the practical implications are straightforward. First, any brand site embedding TikTok or X widgets, pixels, or embeds should expect that the tool — and others like it — can expose those trackers to visitors. Second, communications teams should prepare for the possibility that journalists or users will test their domains and publish the results. Third, privacy compliance reviews that treat cross-site tracking as a hypothetical should treat it as a checkable fact.

The Markup has a track record of platform accountability reporting, and the tool extends that work from investigation into infrastructure. The newsroom frames the update as a service to readers who want to know what happens to their data after they leave an app — a question that has grown louder as regulators on both sides of the Atlantic tighten rules on cross-context behavioral advertising.

What the tool cannot do is equally worth noting for practitioners. Detection of a tracker does not, by itself, establish what data flows through it, how long platforms retain it, or how it feeds targeting models. Those claims require deeper inspection, and platform statements about data use remain the official record unless regulators or reporting contradict them.

Still, the update lowers the barrier for scrutiny. Any user can now check for TikTok and X tracking with a journalist-built instrument rather than a developer console — and the results will likely inform both consumer sentiment and the next round of policy fights over platform data practices.