Quick answer
Data latency is the time between an event happening, such as a page view or purchase, and that event being available to query or see in a report. Data freshness is the related question of how recent the newest data in a report is.
Formula: end-to-end latency = collection delay + transport + ingestion queue + processing + report cache
What is data latency?
Data latency is how long it takes from something happening, a click, a page view, a payment, until you can see it in your data. Low latency means a near-live picture; high latency means you are always looking at the past.
Freshness is the reader's side of the same thing: how old is the newest data on this chart? A report can have low event latency but poor freshness if it only refreshes once an hour.
Where the delay comes from
A sample analytics pipeline (illustrative delays):
| Step | What happens | Typical delay |
|---|---|---|
| Collection | Script batches events or waits for the page to hide | 0–30 s |
| Transport | Request travels to the collector | < 1 s |
| Ingestion | Events wait in a queue and are validated | seconds |
| Processing | Sessions are built, bots filtered, totals rolled up | seconds to minutes |
| Report cache | Results are cached for speed | minutes |
Some values are only known later by design: time on page needs the visitor to leave, Web Vitals are reported when the page is hidden, and a session is only complete after inactivity.
Which reports need real time
| Need | Acceptable latency |
|---|---|
| Launch day, live campaign, checking an install | Seconds |
| Alerts on traffic drops or error spikes | Minutes |
| Daily and weekly reporting | Hours |
| Monthly and strategic decisions | A day is fine |
Chasing real time everywhere costs money and adds noise. Partial data for "today" is also easy to misread as a drop.
How to check it
Send a test event with the current time as a property and note when it appears. Repeat at a busy hour.
In TapCub, Web analytics › Realtime shows a test pageview in the human feed within a few seconds of opening your site, and "online now" counts visitors with an event in the last 5 minutes. See realtime.
Related: real-time analytics and data sampling.
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