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Filters section listing attribution rules by priority with their conditions, operations and tags Every visit arrives with raw signals: a referrer, some UTM parameters, maybe an ad click ID. Attribution rules turn those into a Channel and a Channel Group you can report on.

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Default Rules

A new workspace starts with 39 rules covering paid search, paid social, paid video, display, organic search, organic social, email and direct. They are ordinary rules: you can edit or delete any of them.
Email sits above Direct Traffic deliberately. Many mail clients strip the referrer, so a click from an email otherwise looks like someone typing your address — which is why your broadcasts should carry UTM parameters.
There is no seeded rule for referral traffic. A plain link click from another site matches nothing and lands in not-mapped, by design: it surfaces in the Filters tab so you can classify those referrers once, rather than being quietly bucketed. Add your own rule on Referrer Domain when you want a referral channel.For the same reason, the paid UTM rules require a known source as well as a paid medium — utm_medium=cpc from a network Notifuse does not ship a rule for falls through to not-mapped rather than being called paid.

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How Rules Are Applied

Rules run by priority, highest first, and every matching rule contributes — evaluation does not stop at the first match. Precedence is per target rather than per rule:
  • For each target, the highest-priority rule that writes it wins.
  • A lower-priority rule can still write a target no higher-priority rule claimed. A rule that only sets custom_3 therefore applies even when a higher-priority rule already set the channel.
  • Two matching rules at the same priority both run, and the later one overwrites — a tie goes to the last rule, not the first.
  • set as default never claims a target, so a lower-priority set still overrides a default written earlier. That is how the priority-10 fallback works.

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Writing a Rule

A rule is a set of conditions and the values to write when they all match. All conditions of a rule must match for it to apply. Editing the Google Ads rule: priority, tags, a UTM ID From regex condition, and operations setting Channel Group and Channel
  • Conditions test any tracked signal: the referrer, referrer domain and referrer path, is-direct, the landing page, domain and path, the current path, every UTM parameter and the ad click ID, plus device, browser, browser type, OS, user agent, connection type, language and timezone.
  • Operators are equals, not equals, contains, not contains, is empty, is not empty and regex.
  • Operations then set a value, set it only as a default where nothing else has written one, or unset it.
  • Targets are Channel, Channel Group, any of the five UTM fields, Referrer Domain, Is Direct, and custom_1 through custom_10.
Writing a custom dimension from a rule is how you classify traffic you could not tag at the source — a partner’s referrer becomes a partner name, say, without asking them to add parameters.

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Ad Click IDs

The tracker recognises thirteen ad click ids on the landing URL: gclid, wbraid and gbraid (Google Ads), dclid (Google Display), fbclid (Meta), msclkid (Microsoft), ttclid (TikTok), li_fat_id (LinkedIn), twclid (X), epik (Pinterest), ScCid (Snapchat), rdt_cid (Reddit) and qclid (Quora). The first one present lands in utm_id, and the parameter it came from in utm_id_from — so a paid click is attributable even when the campaign forgot its UTMs. “First” means first in that list, not first in the URL, so a link carrying both gclid and fbclid is attributed to Google. Matching ignores case: ?sccid=, ?ScCid= and ?SCCID= are all recognised, and utm_id_from always records the canonical spelling above — which is what the built-in rules match on.
To capture a click id of your own in addition to those thirteen, set extraAdClickIds: ['myclid'] in NotifuseAnalyticsConfig. adClickIds also exists but replaces the list outright, and adClickIds: [] captures none — use it only when that is what you want. A rule matching on utm_id_from only ever fires for a parameter the tracker was told to capture.

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Changing Rules Later

Rules are applied when a visit is recorded, so editing them changes what happens next, not what already happened. To apply them to existing traffic, run a backfill from the Filters tab. A backfill rewrites the attribution columns on historical session and goal rows — which is what updates “revenue by channel” for past traffic. It never adds, removes or re-times traffic, and pageview rows are not touched at all.
A backfill clears Channel and Channel Group on any row its rules do not write. Those two exist only because a rule said so, so “no rule matches” means empty.Custom dimensions are left alone, because your tracker can set them without any rule being involved. A rule that targets one still rewrites the rows it matches, and an unset_value rule still clears them — but a row no rule matches keeps whatever your site sent. One consequence worth knowing: a custom value written by a rule survives that rule’s deletion, since nothing can tell it from a tracker-supplied one afterwards. Clear it with a temporary unset_value rule.
One backfill runs at a time, per workspace. Cancelling stops it where it is; the partitions already rewritten keep their new values, so a cancelled run leaves your data in a mixed state until you run it again.

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Where the Traffic Comes From

Broadcasts add UTM parameters to their links — see Broadcast Campaigns → UTM Tracking. Those are exactly what the seeded Email rule looks for, so campaign traffic classifies itself with no extra work.

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Notes

  • Attribution is resolved per session, from the landing page. A visitor who arrives from a search and later clicks one of your emails starts a new session with its own attribution once the first has ended.
  • Goals start from their session’s attribution, then re-run the rules with the goal’s own page path. A goal matches its session unless one of your rules tests the current path.
  • The rule set is versioned by a hash the server recomputes on every save. The console compares it against the version of the last completed backfill to warn you when your history was attributed under a different rule set. A backfill rewrites every historical row, not just the stale ones.
  • API Reference