The agents that run your inbox.
Stop triaging threads, chasing replies, and trusting inflated open rates by hand. Four agents do it instead — each with one job, running on rules you write, not a black-box model you have to trust blindly. Built privacy-first, so you always see exactly why an agent did what it did.
- Q3 renewal termsSarah Okonkwo12m ago
- Intro: platform migrationJames Aldrich54m ago
- Following up on last weekPriya Venkataraman1h ago
- Partnership proposal — draft v2Dan Feldman3h ago
- Vendor security questionnaireMei Tanaka5h ago
Four agents running. More on the way.
More agents shipping.
Signum is the agent platform for email — not a fixed product. Today, four. Next quarter, more. The product roadmap is public.
AI Auto-Respond
Drafts a reply in your voice for inbound threads matching your rules. Bring-your-own Anthropic key. You approve before send.
Inbox Sweep
Bulk-triage of low-priority threads — newsletters, notifications, status updates — into a daily digest you read once.
Calendar Catch
Detects meeting-request threads and surfaces conflict-aware scheduling suggestions inside the floater.
Snippet
Saved compose blocks with merge tags, slash-command insertion, per-recipient personalization.
Most “opens”
aren’t opens.
Apple Mail Privacy Protection pre-fetches every pixel. Gmail’s image proxy does the same, less aggressively. Track labels them honestly — partial credit, not full open — so what you see reflects humans, not infrastructure.
How Track verdicts honestly →Verdict distribution · 1,000 sample sends
Only HUMAN counts as a genuine read. Everyone else: excluded or shown with a qualifier.
Wherever you read email.
Chrome extension
Daily driverThread pills, compose carets, inbox engagement column, persistent floater with Watch / Followup / Reminder tabs.
Web dashboard
The consoleEvery sent email, every active sequence, every cohort, every analytics view. Bulk send, templates, billing.
Recipient data, isolated.
Encrypted at rest
Recipient PII encrypted AES-256-GCM under a per-workspace key. 79+ encrypt call sites across the API.
Encrypted in transit
TLS 1.2+ on every leg. HSTS site-wide. No internal HTTP. Cloud Run + Cloudflare + Neon.
No third-party tracking
Zero analytics or advertising trackers on this website or in the product. Your data runs Signum, that's it.
Full disclosure — what we are not — on the Security page.
Stop guessing. Start knowing.
Free up to 100 emails / month. All four agents on day one. More shipping.