Server-side tracking (SST) is a technical answer to browser limits: cookies are shorter-lived, ad blockers reach deeper, and cross-device tracking falls apart. The SST analysis in the Auditor shows whether the switch is even worth it for your property - and if so, how big the expected lever is.
What does the app check?
The SST analysis calculates a weighted score between 0 and 100 from five individual checks and shows the implications for each area:
- Cookie lifetime impact - how do returning rates differ between Safari (short cookies) and Chrome?
- Attribution gap - how many sessions and key events end up without a clean source?
- Funnel duration - how many days typically pass between first contact and conversion?
- Cross-domain - how many different domains are involved?
- SST detection - are there already signs in the
user_pseudo_idpattern that an SST implementation is running?
When is a check triggered?
| Component | Weight | Threshold |
|---|---|---|
| Cookie lifetime impact | 35 % | Safari-vs.-Chrome returning-rate delta |
| Attribution gap | 35 % | Unattributed sessions/key events |
| Funnel duration | 20 % | Days to conversion |
| Cross-domain | 10 % | Number of domains |
| SST detection | - | user_pseudo_id pattern |
Score traffic light: >70 = green, 40-70 = yellow, <40 = red. On top of that, the check flags SST event coverage below 50 % of web events as a warning and a cookieless share >20 % as a risk.
The logic lives in app/pages/serverside_tracking.py,
app/services/sst_check_service.py and in the
OnPage detector app/services/sst/_check_sst_detection_onpage.py.
Common causes of low scores
- Incomplete SST implementation - the web side fires more events than the server endpoint variant, coverage <50 % of web events.
- Attribution mismatch - SST sends a different source/medium combination than the web events (e.g. header-based UTM reconstruction vs. frontend parameters).
- Cookie lifetime problem - SST only sets short first-party cookies (e.g. 24 h), while the web side uses 2-year cookies. Session fragmentation is the result.
How to proceed
- Open the SST tab in the dashboard - the overall score sits at the top, with the five sub-scores and explanations below.
- With a low cookie-lifetime score: look at the Safari and Chrome returning rates side by side. A large delta = SST helps.
- With a high attribution gap: check Attribution & acquisition quality in parallel - sometimes the fix is not SST but a better referral exclusion.
- Before any SST investment, run the OnPage check (OnPage checks - browser-based audit) to see whether the site even responds with custom endpoints and an FPID cookie.