Website script

The Argus website script counts visits and the actions you care about, measures how fast your pages feel, and serves feature flags. It sets no cookies and Argus never stores visitors' IP addresses.

5 min read

Adding the script

Under Argus → Sources, each browser source has a Website script card with its tag. Paste it into your page's <head>:

index.html

html

<script
  defer
  src="https://argus-in.naijacloud.com/sdk/v1/argus.js"
  data-key="<public key>"
></script>

data-key is the public key from the source's DSN. It is public by design, because it lives in the browser. To stop other sites sending with it, list your own sites under Sites allowed to use this key on the same card.

Web analytics on that card switches page-view collection on or off for the source. Changes take effect on the next page load, with no new script to ship.

Options

Attribute	Default	What it does
`data-key`	none (required)	The source's public key. Without it the script sends nothing
`data-env`	`production`	The environment the visit belongs to. Feature flags are evaluated for this environment
`data-persist`	off	Set to `local` to keep an anonymous visitor ID in `localStorage`, so returning visitors are recognised across days

data-persist="local" stores an identifier in the visitor's browser. If you turn it on, your site needs its own consent notice. That is why it is off by default.

What it collects on its own

Page views, including navigations in single-page apps. The referrer and any utm_source, utm_medium and utm_campaign tags are taken from the first page of a visit.
Web Vitals: LCP, INP, CLS, FCP and TTFB.
Rage clicks: three or more clicks in the same spot within a second.
Dead clicks: a click on a button or link that changes nothing for a second.

Privacy

Privacy is decided on the server, so a modified script can't weaken it:

No cookies, and no IP addresses stored. A visitor is a code made from their IP address and browser that changes every day and can't be turned back into either. The script keeps only a per-tab session ID in sessionStorage. One consequence: someone who visits on three days counts as three visitors in a week.
Paths, not URLs. Query strings and fragments are dropped, and the referrer is kept as a host only. Emails, card numbers and tokens are blanked in paths and event properties.
Bots are dropped: crawlers, monitors and scripts are not counted.
The visitor's country comes from the request's edge location data.

Your site is the controller for your visitors' data. Use these facts to update your own privacy notice.

Custom events

Track an event

argus.track('checkout_paid', { plan: 'pro' }, { revenue: 25000, currency: 'NGN' });

argus.track(name, properties, options) records an event with optional properties. options takes value, revenue and currency. Events you send count against your plan's monthly analytics allowance, shown under Argus → Usage & plan.

Identifying signed-in users

Identify

argus.identify(user.id); // when someone signs in
argus.reset();           // when they sign out

Argus stores a hash of the ID, never the ID itself. Identified people are what retention and experiments count; anonymous visitors change every day, so they are left out of retention.

Calling it before the script loads

The tag uses defer, so window.argus doesn't exist until the page has parsed. Queue calls in window.argusq and the script runs them when it loads:

Queue calls

html

<script>
  window.argusq = window.argusq || [];
  argusq.push(['track', 'signup_started']);
</script>

Feature flags

Create flags under Argus → Flags. A flag is on/off or has several variants with weights, and is set per environment with a rollout percentage and optional rules on attributes your app passes.

Read a flag

argus.onFlags(() => {
  if (argus.flag('new-checkout', 'off') === 'on') showNewCheckout();
});

argus.flag(key, fallback) returns the variant this visitor gets, or fallback when the flag doesn't exist. The first read of each variant on a page is recorded as an exposure, which is what experiments count.
argus.onFlags(callback) runs once flags have loaded.
argus.reloadFlags(attributes) evaluates the flags again with attributes for your rules, such as { plan: 'pro' }.

A visitor keeps the same variant: raising a rollout never takes a flag away from someone who already had it. Calling argus.identify reloads flags for the signed-in user.