Sonar is a free tracking scanner for any website. Paste a URL and it crawls the whole site from the outside, the way a visitor's browser does, with no login, no account and no tag access. It captures every outbound tracking request on every page and reports what is actually running: GA4, Google Tag Manager, Google Ads, Meta Pixel and 20+ other ad pixels, analytics and session tools, consent platforms and the dataLayer. Then it lists the problems it can prove, such as duplicate GA4 hits, conflicting IDs, staging containers left on production, tags firing before consent, PII leaking into analytics, and a tag manager with no live tags. Every finding carries its evidence, so nothing is guessed. You get a tracking health score out of 100, a free on-page scorecard, and an email-unlocked full report with a branded PDF. Built by Dolphin Analytics, a London analytics agency, for marketers and founders who want to trust their tracking before they spend on ads. Validated, not hallucinated.