Documentation

Welcome. The docs are organized into three sections: quick start, signals reference, and the API.

Quick start

The fastest way to get started:

• Sign in with your Google account at signum.email.
• Install the browser extension from the Chrome Web Store (search "Signum email").
• Open Gmail. You'll see a Signum toggle next to the Send button. Leave it on.
• Send your next email normally. Watch the dashboard update in real time as it gets read.

The six signals

Signum fires six independent tracking signals from every email:

• Pixel GIF — a 1×1 transparent image. Weight: +20.
• CSS beacon — a stylesheet load. Weight: +15.
• Font beacon — a @font-face declaration. Weight: +12.
• DNS wildcard — a unique subdomain lookup. Weight: +5.
• Link click — an active click on a tracked link. Weight: +45 (capped at 60).
• Gmail API confirm — read confirmation via the Gmail API. Weight: +90.

Engagement tiers

Every recipient gets one of four tiers based on their score:

• NO_SIGNAL · 0–30 · No reliable engagement detected.
• LIKELY · 31–60 · Probably read, but only passive signals fired.
• ENGAGED · 61–85 · Strong signal — multiple corroborating events.
• CONFIRMED · 86–100 · Definitive read.

API reference

The Signum API is REST-over-HTTPS, JSON in and out, authenticated by Bearer token. Full docs and SDKs are coming soon. Email [email protected] if you want early access.