Bot & Spam Filtering
How Pulse's Cerberus engine detects and removes bot traffic from your analytics, and how to review and override decisions.
Pulse uses Cerberus, a purpose-built bot and spam filtering engine, to keep crawlers, scrapers, and spam referrers out of your analytics data. It runs on every inbound session and works without any action from you.
Enable bot filtering
Go to Settings → Bot & Spam and toggle filtering on. The setting is per-site.
How Cerberus evaluates sessions
Each session is scored against a set of signals:
- User-Agent — known bot strings, headless browsers, and automation frameworks
- Referrer reputation — known spam domains and referrer injection patterns
- Screen dimensions — resolutions that do not correspond to real devices
- Language consistency — mismatches between browser language and Accept-Language headers
- Human signals — presence or absence of mouse movement, keyboard input, and scroll events before the first pageview
- Device rules — combinations of properties that do not occur on real hardware
- Datacenter IP detection — traffic originating from cloud provider and VPN IP ranges
- Fingerprint uniformity — sessions where all browser properties are identical at high volume, indicating automation
Sessions that fail these checks are either flagged as suspicious or blocked outright.
Cerberus decisions are non-destructive. Flagged and quarantined sessions are stored separately and can be reviewed and overridden — they are never deleted automatically.
Session review
The Settings → Bot & Spam tab has two review queues:
Suspicious sessions
Sessions Cerberus flagged as probable bots but did not block. Each session shows the risk signals that triggered the flag. You can:
- Flag as bot — confirm the decision and move the session to quarantine
- Mark as human — override the flag and restore the session to your analytics
- Bulk actions — select multiple sessions to flag or restore at once
Quarantined sessions
Sessions that Cerberus blocked outright. If you believe a session was incorrectly blocked, click Unblock to restore it to your analytics.
Domain reputation
The Domain reputation table shows referrer domains that have been evaluated by Cerberus, along with:
| Column | Description |
|---|---|
| Domain | The referrer domain |
| Source | How the reputation was established: seed (built-in list), learned (from your site's traffic patterns), or collaborative (shared signal across the network) |
| Bot ratio | Percentage of sessions from this domain classified as bots |
You can set a per-domain override:
- Allow — always pass sessions from this domain through, regardless of other signals
- Block — always quarantine sessions from this domain
- Reset — remove the override and let Cerberus decide based on signals
Blocking a domain by reputation affects all future sessions from that referrer. Use this for persistent spam sources, not for one-off odd sessions.