TagLens — dataLayer vs GA4 gap inspector

Browse the site; TagLens records every dataLayer push and analytics hit, and shows what should have fired but didn't.

Browse the site. TagLens tells you what tracking fired — and what should have fired but didn't. It records every dataLayer push a page makes and every analytics request it sends, puts them in one timeline side by side, and says which announcements never became a hit. No DevTools, no console, nothing to add to the site. Press record and browse the way a customer would. WHAT IT FINDS • Pushes that never became a hit — the gap where tracking silently breaks — kept separate from the ones nothing was ever configured to send. • Events sent more than once with an identical payload, which inflate counts and revenue wherever they happen. • Problems inside the payloads themselves: a missing required parameter, a value left over from an earlier event, personal data where it should not be. • Controls that produced no tracking when pressed — including ones the Tag Manager container has a trigger for, where the container contradicts itself. • Which measurement IDs actually received what, including server-side tagging on the site's own domain. WHAT YOU CAN DO WITH IT • Read the container. TagLens reads the same Tag Manager container the page already loaded and works out which tag would have sent an event, so a missing hit arrives with a reason rather than a shrug. • Save a journey as a flow, play it again later with one press, and see what changed between two runs. • Judge a session against a written tracking plan. • Ask questions about a recording in plain English — what never arrived, why, and what to fix first — using an AI model you connect with your own API key, or by exporting the recording and reading it in ChatGPT. • Leave with the evidence: JSON for a developer, CSV for a spreadsheet, or a findings page written for someone who does not read dataLayer. PRIVACY TagLens has no server. Nothing it records is transmitted anywhere by default — no account, no login, no telemetry, and no third party receives any of it. Everything stays in your own browser's storage on your own machine. It makes one outbound request of its own: a GET for the same Tag Manager container URL the page has already requested, so that its public definition can be read. No data is sent with it. The one exception is AI analysis, which you switch on yourself by connecting your own API key. Only then, and only when you ask a question, TagLens sends that model a fact sheet about the recording — event names, counts, whether each reached Google Analytics, and the values the site put in its data layer. Parameters that identify a person are listed by name only; their values never leave your machine. Connect no key and nothing is ever sent.