Technical Overview
The Engine.
How it actually works.
Six core systems. Each one built to solve a specific failure mode in outbound email. No magic - just math, routing logic, and DNS work done automatically.
The Pacing Math
10,000 sends a day.
Zero spam flags.
Volume formula
inboxes = 99
cap_per_inbox = 101
daily_total = inboxes × cap_per_inbox
= 9,999 ≈ 10,000
# Per-inbox pacing (warmup day N)
rate = min(N × 3.33, 100) sends/hr
Each inbox stays under its daily cap. Sends are distributed across the hour using Poisson intervals - not bulk bursts at :00 - so no volume spike triggers spam heuristics.
Why this matters
Poisson intervals
Emails spaced by a randomized distribution, not every 36 seconds exactly. ESPs flag machines, not humans.
Per-inbox daily caps
Each sending domain has its own ceiling, set by the warmup curve. Auto-pacing never exceeds it.
Hourly drip mode
Volume spreads across the day in hourly windows. No midnight burst. No 8am flood.
Adaptive throttle
If bounce rate climbs above 0.08% on any inbox, that inbox drops to 50% rate automatically.
Six systems. One price.
Every feature that makes cold email actually work.
Multi-Inbox Rotation
Rotate up to 99 sending domains automatically.
Each campaign draws from your full inbox pool on a weighted round-robin schedule. No domain sends more than its daily warmup cap allows. The scheduler monitors reply rate, bounce rate, and spam classification per domain - if one goes red, it gets benched while the others continue sending.
Auto Warmup
Full inbox trust in 30 days. Runs itself.
Warmup runs as a background job. Each new inbox starts at 5 sends/day, increases by 3.33 per day, and hits 100 by day 30. Warmup emails are exchanged with a private seed network - not your actual leads. Domain health scores recalculate every 6 hours. If a domain drops below 0.75, warmup pauses and you get a notification.
Bounce Protection
Bounces caught before they damage your domain.
Every lead email is validated via MX record lookup before the first send. Hard bounces are removed from the sequence immediately and flagged in the lead list. Soft bounces get two more attempts with a 48-hour gap. If any sending inbox hits 0.1% hard bounce in a 24-hour window, that inbox drops to half-rate mode and a health alert fires.
Reply Detection
Sequence stops the moment they reply.
Reply detection runs on a 60-second polling loop across all connected inboxes. When a reply is detected, that lead is immediately flagged and all pending scheduled sends are cancelled - across every inbox in the rotation. No awkward follow-up hitting someone who already responded. The reply surfaces in the unified inbox, threaded by lead.
DKIM / DMARC
SPF, DKIM, and DMARC. Done on setup.
Core Mail Engine generates the correct DNS records for every connected sending domain on first connection. DKIM keys rotate every 90 days automatically. DMARC policy is set to quarantine by default, with weekly aggregate report parsing - if alignment drops, you get an alert before your inbox rate does.
Unified Inbox
Every reply. Every domain. One inbox.
Replies across all sending domains surface in a single threaded inbox, organized by lead. You never have to log into 12 different Gmail accounts to track conversations. Threads show full context: which sequence triggered the reply, which domain received it, and the full email chain. Reply directly from the unified inbox - responses route out through the same domain that received the original.
Routing Logic
How a send gets routed.
Every email clears seven checkpoints before leaving the server. Each step can abort the send, pause the inbox, or reroute to a backup domain. This is what keeps reply rates above 4% instead of 0.4%.
MX record verified, email format checked, suppression list cross-referenced.
Weighted round-robin picks the healthiest available sending domain.
Current daily_count below warmup_cap? If not, defer to next hour bucket.
Poisson random delay inserted. Send scheduled within the hour window.
Email signed with the domain's current 2048-bit DKIM private key.
SMTP handshake. TLS enforced. Server response code logged.
Lead added to active watch list. 60-second polling begins immediately.
June 2026 Launch
The engine is built.
Ready when you are.
$19/mo. Every feature on this page. No tiers, no upsells. First 200 operators lock in that price for life.
No credit card required - waitlist confirmation only