FourWay.io
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JavaScript SDK (planned).

Planned. Nothing on this page is available yet. We publish the design early so you can tell us if it fits: write to [email protected].

Planned

What it is for

A small script that reports how real browsers experience your pages: navigation timing and Core Web Vitals, from a sample of visits. It is for measurement.

Looking to hold a traffic spike? That is the waiting room script, which works today.

Planned install

<!-- Planned. This URL does not serve a script yet. -->
<script defer
  src="https://cdn.fourway.io/sdk/v1/fourway.min.js"
  data-fourway-site="site_public_123"
  data-fourway-mode="monitor"
  integrity="sha384-…" crossorigin="anonymous"></script>
  • The site ID is public. It is not a secret key.
  • Versioned files with Subresource Integrity hashes, so you know exactly what runs.
  • Loaded with defer, so it never blocks rendering. If our servers are unreachable, it fails silently.

What it will collect

  • Timing stages (connect, first byte, load) and Web Vitals (LCP, INP, CLS).
  • The page path, with query strings and fragments removed.
  • A short-lived random session ID scoped to your site.

What it will not collect

  • Form inputs, request bodies, cookies or authorisation headers.
  • Full URLs, email addresses or full IP addresses.
  • Anything from pages where you have not installed it.

Limits we will keep stating

The script only runs after a page loads, so it cannot see or rescue a request that failed. Visitors with JavaScript off, or with blockers, are not counted, so it estimates sampled sessions, not total traffic. Protecting pages that never load needs a gate in front of your server, our planned Edge Guard.